[Purpose/significance] Clarifying the formation mechanism of collaborative innovation network is the premise to manage collaborative innovation efficiently. [Method/process] Taking the patent data of 101 bio-tech research and development( R&D) institutions as an example,this paper constructs the collaborative innovation network,and tests the formation mechanism of the network by using Exponential Random Graph Model( ERGM). [Result/conclusion]It is found that the network constructed in this paper is a small-...