The toughening effect of SiC particles was applied to inhibition of the cracks in Al2O3 ceramic for Laser Direct Forming (LDF). The experiments of coaxial laser cladding Al2O3 ceramic added SiC particles were performed on the Ti-6Al-4V alloy substrate to investigate the feasibility of Al2O3+SiC composite ceramic by LDF and explore the factors effecting on the crack susceptivity. The cracks, microstructures and the combining of the two compositions were observed by an optical microscopy, and the phase transitions were detected by X-ray diffraction. The results show that some complete SiC particles contained in the Al2O3 ceramic can inhibit the cracks, and the Al2O3+SiC composite ceramic without serious chemical reactions or combining defects can be prepared. The crack susceptivity is significantly affected by the proportion of SiC (f), laser power (P), scanning velocity (v) and the powder flow rate (n). Finally, a thin-wall Al2O3+SiC composite ceramic block(17 mm×6 mm×2 mm)without the obvious defects was formed with the parameters of f,P, v and n in 10%(weight proportion), 186 W, 300 mm/min and 1.78 g/min, respectively.