Ti was introduced into the WMoTaV refractory high-entropy alloy (RHEA) to improve its mechanical properties. WMoTaVTi_x (x=0, 0.5, 1, 1.5, and 2; x denotes the molar fraction, %) RHEAs were synthesized by high-energy ball milling and spark plasma sintering. The effect of Ti addition on the microstructure and mechanical properties of the WMoTaV RHEA was investigated. The results indicated that the addition of Ti significantly enhanced sintering densification and improved mechanical properties of the alloy, with compressive yield strength initially increasing and then decreasing as Ti addition rose. The WMoTaVTi_1.5 RHEA exhibited optimal mechanical properties, with a compressive yield strength of 1862 MPa, fracture strength of 2892 MPa, and fracture strain of 15.63%. Compared with the alloy without Ti addition, the yield strength and fracture strain of the WMoTaVTi_1.5 alloy increased by 35% and 53%, respectively. The improvement is attributed to solid solution strengthening, fine grain strengthening, and TiO_x secondary-phase-particle precipitation strengthening.