To improve the high-temperature oxidation resistance of titanium alloys. Two kinds of Ti∶Al∶Si=41∶41∶18 (at.%) and Ti∶Al∶Si=35∶35∶30 (at.%) composite coatings were fabricated by laser cladding in-situ synthesis on TC4 titanium alloy. The microstructure and phase composition of the composite coatings were characterized by X-ray Diffraction (XRD), Optical Microscopy (OM) and Scanning Electron Microscope (SEM). The oxidation resistance of the coatings and the substrate sample under 800 ℃×24 h×5 times cycle oxidation condition was tested by tube resistance furnace. The mechanism of high-temperature oxidation resistance was analyzed by oxidation kinetics curves and oxidation mass gain. The results show that the cladding coatings are mainly composed of Ti5Si3, Ti7Al5Si12, Ti3Al, TiAl and TiAl3 phases, and there are no epitaxial columnar crystal structures as considered by a general laser cladding coating, all of which are fine equiaxed crystals. Under the condition of 800 ℃×24 h×5 times cycle oxidation, the weight gain per unit area of TC4 substrate is about 35.1 mg·cm-2, and the laser cladding composite coatings are about 2.8 mg·cm-2 and 3.3 mg·cm-2. The high-temperature oxidation resistance of the two kinds of coatings is 12.5 and 10.6 times higher than that of the titanium alloy substrate. The oxidation resistance of laser cladding in-situ synthesis Ti-Al-Si composite coatings has been significantly improved. On the one hand, the continuous dense TiO2, Al2O3 and SiO2 oxide layers have been obtained on the surface, which hinders the diffusion of oxygen and improves the oxidation behaviors. On the other hand, the adhesion of the oxide layer is improved so that the oxide layer is not easily peeled off from the coating surface and the non-oxidized portion of the coating is well protected.