The Zr-0.4Fe-1.0Cr-xMo alloys were prepared by vacuum arc melting method, and its tensile properties at room temperature and 350 °C were measured. Results show that the tensile strengths of Zr-0.4Fe-1.0Cr-xMo alloys are higher than that of Zr-1.0Sn-0.3Nb-0.3Fe-0.1Cr alloy. With the increase of Mo content, the tensile strength decreases at room temperature whereas increases at 350 ℃, which indicates the strengthening effect of Mo on Zr-0.4Fe-Cr alloy at high temperature. The variation of the strain hardening exponent n-value with Mo content is opposite to that of the yield strength. The effect of Mo on tensile properties is related to the change of second phase particles characteristics due to Mo addition.