Aiming at the problems such as high synchronization requirementof information and low fault tolerance of Substation-Area Backup Protection (SABP), an algorithm of SABP based on improved evidence theory fusion is proposed. Firstly, the SABP deviceidentifies the suspected fault lines according to action information of the traditional main/backup protection and direction component at both ends of all substation lines, and forms the evidence fusion information domain using the protection information at both ends of the suspected fault lines. Then, the evidence group is formed by preprocessing the collected the action information of main/backup protection and direction component in the evidence fusion information domain, and the basic probability assignment of each evidence is calculated. The SABP deviceidentifies the fault line by improved evidence theory fusion with the evidence information. The simulation results show that the proposed SABP algorithm has the characteristics of no requirement of information synchronization, small substation-area interactive communication traffic and high information fault tolerance, and can effectively improve the performance of SABP.