A cold patching asphalt additive was synthesized from vinyl siloxane, unsaturated fatty acid, alcohol wetting agent and other basic materials. The solvent cold patching asphalt(SCPA) was prepared with the additive as modifier and diesel as diluent under specific process. The formulation of SCPA was determined according to its viscosity and adhesion test results. Based on the design of (SCPAM) and related technical performance test, the improvement effect of the cold patching asphalt additive was evaluated. The results show that the coarse aggregate gradation is suitable for the SCPAM. The temperature stability of SCPA, adhesion of SCPA to aggregate, tensile strength and cohesion of SCPAM increase significantly with the addition of cold patching asphalt additive. The suggested dosage rate for preparing cold patching asphalt is m(asphalt)∶m(diluent)∶m(cold patching asphalt additive)=(73～77)∶(20～24)∶3. The optimum binder content of SCPAM is 47%50% by mass.