The invention discloses a model change design method of a hydraulic torque converter blade grid system. The method includes the following steps that a hydraulic torque converter designed reversely is selected, and a three-dimensional entity model of the blade grid system is established and converted into a two-dimensional model; the blade grid system is subjected to model change design; the two-dimensional model obtained after model change design is converted into a three-dimensional model, the three-dimensional model is output in an IGES format, a design base line obtained after model change of the blade grid system is read in, and a three-dimensional entity model of the hydraulic torque converter blade grid system is established. The method has the advantages that in the whole design process, the design base line of the blade grid system can be adjusted according to design requirements, the design research and development period of a product is greatly shortened, production efficiency is improved, and the research and development cost of the product is reduced.