In the entrepreneurship investment market of all countries, co-investment is a common phenomenon. Venture capital firms may choose “similar partners” in order to avoid co-investment risk or may pursue bigger investment return to choose “the partners with high resource endowment level” or “heterogeneous partners” to co-invest. Compared with the co-investment with “similar partners”, the co-investment with “the partners with high resource endowment level” or “the heterogeneous partners” can improve the ability to provide incremental service for the start-ups by “resources accumulation” or “resource complementarity”, which is further conducive to the growth of the start-ups. Based on venture capital events of China from 1999 to 2019 in PE Database, by constructing the research samples with “leader-investor-potential co-investor” data feature, the empirical test is conducted on the impact of the co-venture capital partner selection on the growth of the start-ups, and the results show that in co-venture capital partners selection, “the risk avoidance” motivation of venture capital firms is not obvious, and does not show the tendency of choosing “similar partners”, but more firms choose “the partners with high resource endowment level” or “the heterogeneous partners” to co-invest for bigger investment profit based on the motivation of “resource accumulation” or “resource complementarity”. The co-investment of venture capital firms with “the partners with high resource endowment level” can boost the start-ups to obtain continuous financing and patents and further promote the growth of the start-ups. The impact of the co-investment of venture capital firms with “the heterogeneous partners” on the continuous financing and patents of the start-ups is not significant. Thus, venture capital firms should pay attention to resource optimization and the ability to provide incremental service for the start-ups, and try to choose the investment partners who are conducive to “resource accumulation” so as to better boost the growth of the start-ups when choosing co-investment partners. The start-ups should be carefully and scientifically choose the partners and try to choose the partners with high resource endowment levels and who can boost their growth in turn.