Abstract: The scope and depth of firms' inter-organizational R&D collaboration were defined firstly in this research. Then we made analysis on the relationship between the scope and depth of firms' inter-organizational R&D collaboration and enterprise innovation performance. The theoretical assumptions were proposed basd on the theoretical analysis. The sample firms of "communications equipment, computers and other electronic equipment manufacturing" industry were selected from Chinese Industrial Enterprises Database. The scope and depth of Chinese firms' inter-organizational R&D collaboration were measured based on firms' patent cooperation information selected from the patent database of Chinese State Intellectual Property Office. An empirical analysis of the influence of R&D cooperation's on enterprise innovation performance was conducted by applying pooled OLS method. There is an optimal scale of the scope of firms' inter-organizational R&D collaboration by taking the enterprise innovation performance into consideration. Meanwhile the deepening of firms' inter-organizational R&D collaboration helps to improve enterprise innovation performance.

Key words: R&D collaboration, enterprise innovation performance, scope of collaboration, depth of collaboration