Performance assessment is an important component of enterprisespsila strategy implementation and control. This paper proposed an E-commerce performance assessment method based on the D-S theory and the Balanced Score Card (BSC) method. With the BSC method, this paper analyzes the primary factors which should be considered to assess an E-commerce companypsilas performance from four aspects: the enterprise operating ability, the exterior customer relations, the Staff's growth degree and the financial aspects. Also, this paper establishes the E-commerce performance assessment indicator system, and then establishes the performance assessment inference model with D-S theory method. Finally, this paper proves this methodpsilas usability through an example analysis.