Open innovation emphasis on integration of internal and external innovation resources, and on the external marketing channels of new products or new technologies to improve firms' innovation ability. According to the properties of open innovation, this paper divides the manufacturing industries into three catalogs. Using Tobit regression analysis, this paper empirically verifies the impact of industry characteristics and firm size on the search tactics. Results show that the external search breadth and depth are all curvilinearly (taking an inverted U-shape) related to performance in each catalog. This paper also reveals that the firm size has a strong positive impact on the degree of openness.