Tests on flexural performance of double-sided precast concrete composite sandwich shear wall with different spacing of connectors and thickness of thermal insulation layers were conducted. Finite element models of composite sandwich shear wall with the same design parameters as test specimens were established, and the crack load and crack development calculated by the finite element method were in good agreement with the experimental results, verifying the reliability of the finite element model. Numerical analyses under horizontal load condition and casting concrete condition were carried out, which showed that the exterior concrete wythe of wall did not crack under horizontal load condition, and the internal force of the truss connector increased with the increase of the connector spacing. When the connector spacing was 600 mm, the safety factor of the connector was about 2 under horizontal load. The internal force of the connector under casting concrete condition is larger than that under horizontal load condition, which is the control design case for the connector.