The invention provides a control method for a superplastic forming process. According to the technical key points, the control method comprises the steps that 1, the relationship between the volume change of a cavity formed in the forming process and the air pressure change in a sealed box is established; 2, a pressurizing curve in the part forming process is designed; and 3, the designed pressurizing curve is corrected according to the air pressure change of exhausted gas. According to the technical scheme, the air pressure change of the vacuum sealed box can be monitored in real time, monitoring of the superplastic forming process is indirectly achieved, the forming degree and integrality are accurately judged, the number of the test times is greatly decreased, and the development periodis shortened so that the best pressurizing curve can be obtained, and the production efficiency is improved.