Collaborative commerce has recently become a killer application of information technology for business collaboration, which helps business sustain their competitive advantage by information sharing, process integration and collaboration. However, not many companies actually adopt collaborative commerce because of its complexity and high cost. This study is to examine critical factors of collaborative commerce adoption. An integrated model was conducted based on innovation diffusion theory. Four constructs (including: characteristics of collaborative commerce technology, organizational characteristics, environmental characteristics, and decision maker characteristics) and eighteen factors are included. The discriminant analysis results indicate that relative advantage, technological compatibility, organizational compatibility, observability, employees' IT skill, business scale and trust toward partners are those critical factors.