For 980 nm high-power semiconductor lasers,suitable reflectivity coefficient of cavity surface films of lasers have been designed.Three kinds of AR-coatings for 980 nm high power semiconductor laser were designed and prepared,the reflectivities of AR-coatings are respectively 8%,5% and 2%,while the reflectivities of HR-coatings are all above 90%.After packaging,luminescence properties of the semiconductor lasers were tested.Compared with non coated laser,output power of the coated laser increased by 35.18%-37.35% when the input current is 15 A,and the conversion efficiency increased by 25.33%~27.44% at their optimum operating point.When the reflectivity of HR-coatings of high power semiconductor laser is constant,the input current value of the optimum operating point is inversely proportional to the reflectivity of HR-coatings.The experimental results show that the semiconductor laser with reasonable cavity surface film can have greater current value at optimum operating point,and this optimized semiconductor laser is suitable for high power operation.