In this paper, a finite element analysis model of a precast reinforced concrete sandwich insulation wall (PRCSIW) is established according to the out-of-plane static load test of the wall. With the consideration of the structural characteristics of PRCSIW, the influences of insulation layer thickness, insulation material type, fastening piece type and fastening piece distribution mode on the mechanical performance of the wall is analyzed. Our work gives a theoretical basis for the optimal design of precast sandwich insulation walls.