The p-type Ohmic contact of Ti/Al/Au multiple metal alloy for 4H-SiC avalanche photodetector(APD)was investigated and the lowest specific contact resistance of 5.4×1O^－4 ΩC cm² was achieved by the linear transmission line method(LTLM). The scanning electron microscope(SEM),Auger electron spectroscopy(AES),X-ray photoelectron spectroscopy(XPS)and Panalytical X'pert PRO X-ray diffraction(XRD)were measured to analyze the contact morphology,chemical composition and the phase formation of the samples before and after annealing. In addition,the electrical properties of 4H-SiC APDs with the same p-type Ohmic contact were also measured. Near the breakdown voltage of about－55V,the voltage descent at p electrode was as low as 0.82 mV,which showed that the Ohmic contact can satisfy the requirement of 4H-SiC APD.