In the background of rapid growth of patent application and quick technology renewal, most countries’ patent systems is facing increasingly serious challenge of patent examination delay, China as well. Extended time-lag may result in reduced motivation effect made by patent system upon technology innovation and even may hinder technology innovation. This project constructs an improved model of patent propensity, analyzes the general mechanism of the patent examination delay working on technology innovation, and points out the optimizing direction of the policy to control the patent examination delay. Furthermore, this project establishes a queuing model of patent examination delay and grant quality, analyzes the equilibrium conditions and patterns of patent examination delay and patent quality, and then reveals constraints of policy affecting patent examination delay. Meanwhile, through an empirical research on China’s patent data granted over the past 20 years by the method of survival analysis, it finds out main factors affecting patent examination delay and offers the policy controlling point of the patent examination delay. Finally, while keeping the inner balance of patent grant system and maximizing motivation effect of patent system on technology innovation, this project chooses the effective policy operating points and provides the policy optimizing scheme of controlling patent examination delay.