diff --git a/Action.js b/Action.js
index ded3ef1..a337798 100644
--- a/Action.js
+++ b/Action.js
@@ -1,5 +1,6 @@
 const Ling = require('so.ling')
 const ticCrypto = require('tic.crypto')
+const TypedActionList = {}
 
 /** ****************** Public of instance ********************/
 
@@ -61,7 +62,7 @@ MOM.verifySig = async function() {
   return result
 }
 DAD.verifySig = async function (actionData) {
-  let typedAction = new wo[actionData.type](actionData)
+  let typedAction = new TypedActionList[actionData.type](actionData)
   return await typedAction.verifySig()
 }
 
@@ -69,7 +70,7 @@ MOM.verifyAddress = function () {
   return this.actorAddress === ticCrypto.pubkey2address(this.actorPubkey)
 }
 DAD.verifyAddress = function (actionData) {
-  let typedAction = new wo[actionData.type](actionData)
+  let typedAction = new TypedActionList[actionData.type](actionData)
   return typedAction.verifyAddress()
 }
 
@@ -77,38 +78,27 @@ MOM.verifyHash = function () {
   return this.hash === ticCrypto.hash(this.getJson({ exclude: ['hash', 'blockHash'] }))
 }
 DAD.verifyHash = function (actionData) {
-  let typedAction = new wo[actionData.type](actionData)
+  let typedAction = new TypedActionList[actionData.type](actionData)
   return typedAction.verifyHash()
 }
 
-DAD.build = async function (action, keypair) { // Applicable on client. 客户端调用 Action.build，即可新建、并打包成一个完整的子事务，不需要亲自调用 constructor, packMe 等方法。 
-  if (action && action.type && keypair && keypair.seckey && keypair.pubkey) {
-    let typedAction = new require(`./${action.type}`)(action)
-    if (typedAction.validateMe()) {
-      await typedAction.packMe(keypair)
-      return typedAction
-    }
-  }
-  return null
-}
-
 MOM.validateMe = function() { // Applicable on chain server. 子类应当覆盖本方法，静态的检查事务内容的格式和语义，是否符合该子类事务的特性要求。To validate an action's content format. 
   // to implement in subclasses: 检查子类事务内容的格式
-  let typedAction = new wo[this.type](this)
+  let typedAction = new TypedActionList[this.type](this)
   return typedAction.validateMe()
 }
 DAD.validate = function (action) { // Allicable on both client and chain server. 
   mylog.info(`Validating action type=${action.type} of hash=${action.hash}`)
-  let typedAction = new wo[action.type](action)
+  let typedAction = new TypedActionList[action.type](action)
   return typedAction.validateMe()
 }
 
 MOM.executableMe = async function() { // Applicable on chain server. 子类应当覆盖本方法，动态的检查事务内容，在当前链状态下，是否能执行。To check if an action is executableMe given the current chain status.
-  let typedAction = new wo[this.type](this)
+  let typedAction = new TypedActionList[this.type](this)
   return await typedAction.executableMe()
 }
 DAD.executable = async function(action) { // For chain server.
-  let typedAction = new wo[action.type](action)
+  let typedAction = new TypedActionList[action.type](action)
   if (typedAction.hasOwnProperty('executableMe')) { // 防止子类忘了定义自己的 executableMe
     return await typedAction.executableMe()
   }else {
@@ -117,18 +107,33 @@ DAD.executable = async function(action) { // For chain server.
 }
 MOM.executeMe = async function() { // For chain server. 子类应当覆盖本方法，执行事务，记录其（除了存入 Action 数据表之外的）副作用到内存数据库或其他地方。
   // to implement in subclasses: 把action的影响，汇总登记到其他表格（用于辅助的、索引的表格），方便快速索引、处理。每种事务类型都要重定义这个方法。
-  let typedAction = new wo[this.type](this)
+  let typedAction = new TypedActionList[this.type](this)
   return await typedAction.executeMe()
 }
 DAD.execute = async function (action) {  // For chain server.
   mylog.info(`Excecuting action type=${action.type} of hash=${action.hash}`)
-  let typedAction = new wo[action.type](action)
+  let typedAction = new TypedActionList[action.type](action)
   return await typedAction.executeMe()
 }
 // [todo 20190411] 执行事务池中的所有事务
 // DAD.executePool = async function() {
 // }
 
+DAD._initTypes = function(types) {
+  Object.extend(TypedActionList, types)
+}
+
+DAD.build = async function (action, keypair) { // Applicable on client. 客户端调用 Action.build，即可新建、并打包成一个完整的子事务，不需要亲自调用 constructor, packMe 等方法。 
+  if (action && action.type && keypair && keypair.seckey && keypair.pubkey) {
+    let typedAction = new TypedActionList[action.type](action)
+    if (typedAction.validateMe()) {
+      await typedAction.packMe(keypair)
+      return typedAction
+    }
+  }
+  return null
+}
+
 /**
  * 获取一批交易，在出块时调用。调用actionPool的内容被深拷贝到currentActionPool后自动清空。
  * 所以在一次出块期间只能调用一次
@@ -165,8 +170,8 @@ DAD.api.prepare = async function (option) {
     } catch (error) {}
   }
   // 前端发来action数据，进行格式检查（不检查是否可执行--这和事务类型、执行顺序有关）后放入缓冲池。
-  if (option && option.Action && option.Action.type && wo[option.Action.type] && option.Action.hash && !DAD.actionPool[option.Action.hash]) {
-    let typedAction = new wo[option.Action.type](option.Action)
+  if (option && option.Action && option.Action.type && TypedActionList[option.Action.type] && option.Action.hash && !DAD.actionPool[option.Action.hash]) {
+    let typedAction = new TypedActionList[option.Action.type](option.Action)
     if (typedAction.verifyAddress() && // 只检查所有事务通用的格式
         await typedAction.verifySig() &&
         typedAction.verifyHash() &&
@@ -176,7 +181,7 @@ DAD.api.prepare = async function (option) {
       DAD.actionPool[option.Action.hash] = typedAction
       DAD.actionPoolInfo.totalAmount += option.Action.amount || 0
       DAD.actionPoolInfo.totalFee += option.Action.fee || 0
-      wo.Netnode.broadcast({ Action: option.Action })
+      TypedActionList.Netnode.broadcast({ Action: option.Action })
       return option.Action
     }
   }