针对已有产品功能创新设计过程不能及时、动态地反应用户需求的问题，应用需求进化定律将不同的用户需求进行预测并规划明确产品的需求目标。通过建立需求目标与功能进化的相互关系，针对不同的需求目标选取对应的功能进化改进定律对已有产品从功能层面进行系统设计。功能改进后满足的需求又可以重新作为产品的调查需求，发现用户的新需求或已有需求的发展，进而再次驱动功能创新设计来满足用户需求，实现功能进化随需求的进化而进化，从而为功能创新设计提供一种新方法。在此基础上提出了已有产品的功能创新过程模型，并以TTSJ900架桥机创新设计为例验证了该模型的合理性。

Aiming at the problems that innovative design process of existing products cannot timely and dynamically response to users’ requirement,the application requirements evolution law forecasts different demands of customers and plans the demand target of clear products. By establishing the relationship of the demand target and the functional evolution,to choose corresponding functional evolutions in connection with different demand targets for improving the law and making the system design for the existing products from the functional level. After functional improved,needs which are met can be regarded as investigation demands of the products again to find the new needs or development of existing needs of customers,and to prompt the functional innovation design for meeting the customers’ needs again,in order to achieve the functional evolution with the evolution of demands,so as to provide a new way for functional innovation design. On this basis,the function innovation procedure model of current product is proposed and the innovation design of TTSJ900bridge girder erection machine has been taken as an example to verify the rationality of the model.