The effects of Mo and Zr on the microstructure and mechanical properties of a novel α+β titanium alloy, Ti575, were investigated. Ti575 alloys with different contents of Mo and Zr, including Ti-5Al-7.5V-0.5Si (Ti575), Ti-5Al 7.5V-1Mo-0.5Si (1Mo), Ti-5Al-7.5V-1Zr-0.5Si (1Zr), and Ti-5Al-7.5V-0.5Mo-0.5Zr-0.5Si (0.5Mo-0.5Zr), were obtained via vacuum arc melting. The four alloys were treated with β single-phase region solution at 940 ℃ for 1 h, followed by two-phase aging at 550 ℃ for 6 h, and then subjected to tensile testing and microstructure characterization. The experimental results show that with increasing Mo content, the lamellar α and secondary α sizes of the Ti575 alloy significantly decrease. The refining effect of Zr on the α phase is weaker than that of Mo. Zr addition reduces the nucleation energy of silicide. Many silicide precipitates are observed in the Ti575-1Zr alloy, whereas no significant silicide is observed in the Ti575, 1Mo and 1Zr alloys. For the Ti575-1Mo alloy, Mo has a significant solid solution strengthening effect, and the α refinement of the lamellae and secondary microstructure significantly shorten the mean free path of dislocation slip. Therefore, the tensile strength (UTS) of the alloy is significantly greater than that of the Ti575 alloy, while the elongation (εf ) decreases accordingly (UTS: Ti575:956 MPa, 1Mo: 1 046 MPa; εf : Ti575: 13.6%, 1Mo: 9.4%). For the Ti575-1Zr alloy, the lamellar α and secondary α are not significantly refined compared with those of the Ti575 alloy, and the strength improvement is attributed to the solid solution strengthening of Zr and the silicide precipitation strengthening. However, the strain mismatch between the silicide and the matrix promotes pore nucleation and decreases the rate of elongation (UTS: Ti575; 956 MPa, 1Zr: 995 MPa; εf : Ti575; 13.6%, 1Zr: 10.8%). For the 0.5Mo-0.5Zr alloy, on the one hand, 0.5 wt.% Mo can refine the α lamellar structure without making it too tiny. On the other hand, 0.5 wt.% Zr not only plays a role in solid solution strengthening but also avoids excessive precipitation of interfacial silicides.Compared with that of the Ti575 alloy, the strength of the 0.5Mo-0.5Zr alloy is greatly improved under the combined action of Mo and Zr, while its plastic loss is insignificant, leading to the best strength-ductility synergy(UTS: Ti575: 956 MPa, 0.5Mo-0.5Zr: 1 053 MPa; εf : Ti575: 13.6%, 0.5Mo-0.5Zr: 11.8%).