As an important step enhancing regional innovation,researches on collaborative innovation have attracted much more atten-tion recently.One significant reason is that cities can get excessive benefits while they take collaborative innovation activities.Based on the theories of innovation geography,this paper takes the collaborative innovation of the Yangtze River Delta (YRD) Urban Agglomera-tion as a case study and measures the collaborative innovation capacity from innovation actors and innovation cities by adopting the catastrophe progression model.Then on this basis,the study depicts the spatial pattern and the benefit allocation of collaborative innova-tion by using the coupling collaborative degree model and benefit allocation model of collaborative innovation.The results show that:1) The collaborative innovation capacity of cities in the Yangtze River Delta has strengthened largely,while the capacity still is not high enough.Cities with high collaborative innovation capacity are concentrated in Shanghai,the southern part of Jiangsu,and Hangzhou Bay,yet the cooperation of the universities-industries-research institutes need to improve.2) The spatial pattern of collaborative innova-tion of the Yangtze River Delta presents several innovation circles,which are in Suzhou-Wuxi-Changzhou Metropolitan Circle,Nanjing Metropolitan Circle,Hangzhou Metropolitan Circle,Ningbo Metropolitan Circle,and Hefei Metropolitan Circle.Shanghai plays the role of the central city of collaborative innovation,while Suzhou,Nanjing,Hangzhou,Ningbo,and Hefei act as sub-central cities.3) The be-nefit each city allocated from collaborative innovation activities has increased.However,the allocations of the benefit show that cities with higher innovation capacity have significant advantages in most cases,which lead to serious disparities in space.