Abstract: By introducing β-tricalcium phosphate (β-TCP) particles into the magnesium matrix alloy, the mechanical and corrosion degradation properties of the composite could be adjusted to meet the service requirements of different implantation sites. In this study, on the basis of mechanical stirring casting, the melt of Mg matrix composite was assisted by ultrasonic treatment, and the β-TCP/Mg-Zn-Ca biodegradable composite was prepared with the β-TCP content of 1% (mass ratio), Zn content of 3% (mass ratio) and Ca content of 0.2% (mass ratio). The effects of ultrasonic treatment on the microstructure, mechanical properties and corrosion behavior of the β-TCP/Mg-Zn-Ca composite were analyzed. The results show that the ultrasonic treatment can refine the microstructure and facilitate the uniform dispersion of the β-TCP particles in the matrix alloy. The corrosion resistance of the β-TCP/Mg-Zn-Ca composites is improved after ultrasonic treatment; The yield strength, ultimate tensile strength and elongation of the as-extruded β-TCP/Mg-Zn-Ca composite after ultrasonic treatment are 211.54 MPa, 334.32 MPa, and 7.28%, respectively, which increase by 8.44%, 4.67% and 17.99%, respectively, compared with the unsonicated β-TCP/Mg-Zn-Ca composite.