To improve the mechanical properties of YSZ thermal insulation coating,clarify the formation process and mechanism of its structure and find the optimal laser processing parameters.The Ti/7YSZ composite coating system was prepared on TC4 surface by laser cladding with YLS-3000 fiber laser system.The macro morphology,microstructure,element distribution,phase composition and hardness distribution of Ti/7YSZ composite thermal barrier coating were characterized by optical microscope,SEM,EDS,XRD and hardness tester respectively.The results show that:the surface of the cladding layer is yellow to varying degrees at different laser scanning speeds,the microstructure of the cladding layer is characterized by "fine in the upper and lower,thick in the middle",which is mainly composed of acicular α′ martensite,martensite core,residual β phase and MC carbide represented by TiC,Zr elements are enriched in the bonding zone of matrix and cladding zone.The Zr element distribution becomes more and more uneven,the martensite fragmentation in the cladding zone is intensified,and the hardness level increases and then decreases as the scanning speed increases.The cladding layer forms a metallurgical bond with the substrate at 7mm/s,and the average hardness level reaches a peak of 600 HV,which is 2.5 times of TC4 matrix,and the cladding quality is the best.Conclusions show that optimization of laser scanning speed can significantly improve the quality and comprehensive performance of cladding layer.Zr element exists in the cladding zone in the form of ZrO2,ZrC and solid solution.The microhardness can be enhanced by the dislocation slip resistance between martensite,strengthening phases such as TiC,and the solid solution strengthening effect of Zr element.