This paper focuses on Small and Medium Enterprises (SMEs) adoption decision of B2B e-marketplace in China. The purpose is to identify the factors driving or hindering SMEs to adopt B2B e-marketplace. First, based on Rogers's innovation diffusion theory (IDT), eReadiness Model and TOE (technology-organization-environment) framework, theoretical model is formulated and ten key factors are identified. Then, a case study is presented. The top manager of four SMEs (two of them have adopted B2B e-marketplace and two of them have not adopted B2B e-marketplace) located in China are interviewed, for the purpose of find out the influence factors they considered when they make a decision of adopting B2B e-marketplace or not. Finally, the result and conclusions are presented.