Patent portfolio plays an important role in strengthening intellectual property protection and helps to continuously improve innovation performance of knowledge-intensive enterprises. Patent portfolio is also the basic analysis unit for patent management. However, there is a lack of empirical research on the mechanism of patent portfolio to influence innovation performance. This paper tries to build a theoretical model to illustrate how patent portfolio diversity and the technical scope influence innovation performance using knowledge-based theory. Through regression analysis of 99 enterprises in the electronics and communication equipment manufacture industry from 2013 to 2017, the results show that technical scope has a significant positive impact on enterprise innovation performance, while patent portfolio diversity presents reverse U relation with enterprise innovation performance. Technological integration competence plays an intermediary role between the patent portfolio and innovation performance. Claims of patent portfolio positively moderate the relationship between technological integration competence and innovation performance.