In this paper, Mg-3Gd-2Zn-0.5Zr-xTi(wt.%)(x=0,0.5,1.0,1.5) alloys were prepared, and the effect of Ti addition on the microstructure and mechanical properties of as-cast and extruded Mg-3Gd-2Zn-0.5Zr-xTi alloys was investigated. The results indicate that the as-cast Mg-3Gd-2Zn-0.5Zr alloy is composed of α-Mg matrix, W (Mg₃Zn₃Gd₂) phase distributed in a discontinuous network at grain boundaries and a granular distribution within grains, and clustered Zr particles. With the addition of element Ti, α-The Mg matrix and W phase were both refined, while the clustered Zr particles were dispersed, and Ti and Zr particles were coexisting. The average grain size of as-cast alloy with 1.5wt.% Ti element is 49.84μm, whose tensile strength is 201.63MPa, yield strength is 102.96MPa, and elongation after fracture is 16.02%. Mg-3Gd-2Zn-0.5Zr-xTi alloys underwent complete recrystallization after extrusion deformation, and the average grain size of the alloy decreased from 4.41μm with the addition of Ti element dropped to 1.98μm,whose mechanical properties are further improved. The extruded alloy containing 1.5wt.%Ti obtained excellent mechanical properties after annealing, with a tensile strength of 322.69 MPa, a yield strength of 260.78 MPa, and an elongation of 15.17%.