Abstract: SiC_p/AZ37 magnesium alloy composites with different mass fractions (0,5%,12%) of SiC_p were prepared by semi-solid injection molding. The effects of SiC_p addition amount on the microstructure, tensile properties and low cycle fatigue properties were studied. The results show that the composites with different SiC_p addition amounts were composed of primary α-Mg, β-Mg₁₇Al₁₂ precipitates and SiC_p. Comparing with AZ37 magnesium alloy, the grain size of the composite was significantly refined, the number of precipitates decreased, the yield strength and elastic modulus increased, and the percentage elongation after fracture decreased. With the increase of the SiC_p addition amount, the tensile fracture mode changed from ductile fracture to ductile and brittle mixed fracture and brittle fracture. With the increase of SiC_p addition, the cyclic hysteresis ring became narrow, and the low cycle fatigue life was first extended and then shortened. The cyclic response was initial cyclic softening and then cyclic hardening until failure, and the cyclic hardening degree increased.