Abstract:The Yangtze River Delta region is known as the "engine of China's economic growth." Cross-regional collaborative innovation is an inevitable choice for the comprehensive upgrading of regional innovation. However, factors such as regional barriers have seriously hampered collaborative innovation among regions. This paper takes Jiangsu, Zhejiang and Shanghai as research objects, and combines the panel data of 2008-2016 in three places to explore the influence of institutional proximity, cognitive proximity and economic proximity on collaborative innovation performance. The empirical results show that economic proximity and institutional proximity can promote the improvement of collaborative innovation performance; the relationship between cognitive proximity and collaborative innovation performance is inverted U-shaped. The model measurement results show that the cognitive proximity among Jiangsu, Zhejiang and Shanghai regions is high, which has inhibited the synergistic innovation performance. Economic proximity and institutional proximity are still in a positive impact on cross-regional collaborative innovation performance. Break down administrative barriers, strengthen division of labor and cooperation, optimize industrial structure, close economic cooperation and narrow the gap in economic development are the bases for promoting economic and social integration in the Yangtze River Delta.