Ni50-xMn29+xGa21(x=0-4) polycrystalline alloys were prepared by the technique of directional solidification and the effect of the component on the martensitic transformation temperature and magnetic properties of the alloys was analyzed. The results show that the martensitic transformation temperatures (Ms) increase and the martensitic transformation hysteresis (ΔT) decrease with increasing of x when x≤3. When x=3, Ms is increased to 309.6 K and the Curie temperature Tc is 360 K. But with x increasing continuously to 4, Ms decreases to 283.2 K and Tc is 362 K. The Ni47Mn32Ga21 alloy exhibits a large saturated magnetic-induced strain of –700×10-6 without stress at room temperature, whose corresponding magnetization intensity is 4.5×105 A/m