The invention relates to a modeling method of a blade for an air compressor. The modeling method of the blade for the air compressor comprises a step I of orderly sequencing and dividing the profile surface, according to a direction in which an air current flows along the profile surface of a blade profile, of the blade profile of the air compressor into four characteristic areas of an expansion accelerating section, a shock wave diffusing section, a behind-shock-wave pressure recovering section and a near-trailing-edge pressure surface recovering section; a step II of controlling the four characteristic areas in step I by adopting mean camber lines respectively, namely controlling the mean camber line of the whole blade profile by the four mean camber lines, and finally determining the geometric parameters of the mean camber line of each section. According to the modeling method of the blade for the air compressor, which is provided by the invention, the flow characteristics, at each section of the blade, of the air current are used as a theoretical basis; the blade is divided into four sections to carry out modeling according to the flow characteristics of the air current; the modeling method of the blade for the air compressor more adapts to the actual flowing process of the air current; meanwhile, a modeling calculation program is an independent computing block; the blade profile can be adjusted by only needing to determine several input parameters; compared with a conventional modeling method, the modeling method of the blade for the air compressor has more degrees of freedom, and is also quite convenient to operate.