To obtain high-quality TiNiTa coating on the surface of TC4 titanium alloy,using ANSYS WORKBENCH software and 3D Gaussian heat source,numerical simulation of the laser cladding TiNiTa powder process was carried out； and the temperature field cloud pattern distribution,the effects of laser power,scanning speed and defocus length on the temperature field were studied.The results show that the microstructure of the cladding layer was compact and fine with good metallurgical bonding to the substrate when the energy density was 1698 J/mm2.The maximum temperature in the center of molten pool increased with the increase of laser power and decreased with the increase of heat source moving speed and defocus length.In addition,the corrosion resistance of TC4 titanium alloy surface was significantly improved.The optimal process parameters were determined by combining simulation and experiment:laser power was 100 W,scanning speed was 2.5mm/s,defocus length was 10mm,pulse width was 5 ms,and frequency was 10 Hz.In addition,the analysis shows that the energy density is an important factor affecting the structure and performance of the cladding layer,and the correctness of the simulation model and feasibility of the method can also be verified by experiments.