Ordinary alloy steel samples were digested in a microwave digestion system. The parameters of microwave digestion (including system of acid, time, power, and pressure) were optimized. Extraction method was used to eliminate the interference of Cu、Fe、Mn ion on Ni from the ordinary alloy steel samples. The nickel content in the samples was determined by ordinary pressure spectroscopy method. The relative error of microwave digestion is less than 1.67% and the RSD(n=5) is less than 1.24%. It is less than general method that is relative error of 2.67% and RSD（n=5）of 3.72%.