Based on modified gravity model, spatial association network of technological innovation was constructed among urban cities in the Yangtze River Economic Belt (YREB). SNA method was applied to explore out their evolution characteristics during 2013-2018. Results are as follows. This network shows lower density, higher efficiency and rigid stratification properties. Such typically central cities as Chengdu and Chongqing cities of upper YREB region show increasing influences significantly of the association network. Wuhan and Changsha cities of middle region of YREB are playing roles as more significant middleman. And such downstream region as surrounding Shanghai city keeps the core power source of YREB network. Based on small cluster analysis, these cities are classified into four blocks and their members changed. In 2018, the four blocks are “bidirectional spillover”, “net spillover”, “net beneficial” and “broker”. Therefore, policy implications are put forward to optimizing technological innovation network structure among urban cities of YREB with respect to regional innovation coordination development.