合约的不完全性直接导致两级供应链上制造商创新投资套牢问题。在信息对称时，通过增加合约重谈机制，双方能够在一定程度上弥补不完全性。当合约用来促进供应链上下游企业间交易并且制造商从事成本降低投资时，由于存在套牢问题一般不能执行供应链最优的投资水平。通过设计协调机制，即签订初始合约并允许事后重谈可以激励制造商达到供应链最优投资水平并且给出初始合约。最后针对一个特例给出了更加具体的结果并通过数值算例对研究结果做了说明。  

Contract incompleteness directly leads the manufacturer innovative investment to be hung up at the buyer-supplier relation. The parties can make up for this incompleteness to some extent by building into the contract a mechanism for revising the contract as each of them receives symmetric information. when a contract is being used to facilitate the trade between a supplier and a manufacturer who must undertake cost reducing investments, there is generally no possibility to implement the first-best for the supply chain because of hung up problem. Designing a coordinative mechanism, by which the parties can rescind the original contract and write a new one, can stimulate manufacturer to implement the first-best investment and derive an optimal initial contract. Finally, some more detail outcomes are derived from a special model and illustrated by an instance.