The invention discloses a titanium-nickel shape memory alloy coating and a preparation method thereof, and provides a process for preparing a composite coating by using a sol-gel method on the surfaceof a Ti-Ni memory alloy. According to the appropriate process parameters for preparing the SiO2 composite coating by using the sol-gel method, the mass ratio of polyvinyl alcohol (PVA) to tetraethylorthosilicate (TEOS) is 1:4, the lifting speed is 2 mm/min, and the sintering temperature is 550 DEG C. The uniform and dense SiO2 coating is formed on the surface of the Ti-Ni shape memory alloy subjected to coating through the sol-gel process, and bonding strength between the coating and a base body is good; and reasonable process parameters are determined for the composite coating process, andan ideal coating preparation effect is obtained.