A data fusion method based on relay protection action model and power grid fault characteristics is proposed for implementing the primary fault correlation recognition in the fault information system. Based on the comprehensive analysis on the fault information of relay protection device， power grid fault judgment and fault information fusion for the two-terminal of line， various applications such as: primary fault correlation of relay protection action signal， judgment of power grid continuous faults， summary of fault reports and the realization of two-terminal fault location algorithm， etc. are emphatically described.