Based on the analysis of the inadequacies of existing credit evaluation model for e-commerce, a multi-dimensional transactions credit evaluation system applying for e-commerce is given and key factors affecting the credit of e-commerce transactions are extracted in this paper. The author proposes three methods for the calculation of transactions credit. They're static integration calculation, dynamic integration calculation in different dimensions and index calculation method. A multi-dimensional credit evaluation model of E-commerce transactions is established and some recommendations on the credit information reveal are given by the author.