Ni44.9Fe4.3Mn38.3Sn12.5 microwires with diameter 40-80 μm were fabricated on a large scale. The magnetization difference between austenite and martensite phase was enhanced after annealing. The wires produce magnetic entropy change 6.9 J/kg·K with 20 K cooling span due to martensite transformation at 50 kOe. The wires show magnetic entropy change -3.7 J/kg·K and working temperature span 85 K due to magnetic transition at 50 kOe.