By means of SEM, XRD, DSC and a materials testing machine, the effects of γ phase on the martensitic transformation temperature Ms, mechanical properties and shape memory effect of Co44Ni26Ga30 alloy with different heat-treatments were investigated. Results show that the volume fraction of γ phase increased with prolonging the holding time during the heat treatment, giving rise to the decrease of Ms. The introduction of γ phase improved the ductility of the alloy greatly while deteriorated the shape memory recovery ratio. Upon appropriate thermo-mechanical training, the shape recovery ratio can be enhanced significantly to 93%.