With the impedance of both the transmission element and load taken into account， the formula for the conversion of the composite induction motor load model from the low voltage side to higher voltage side is derived. The structure of the equivalent load model is the same as the original one， with only part of the parameters modified to describe the dynamic load characteristics on the high voltage side. The formula can provide a theoretical basis to load modeling methodology. The simulation results have verified the correctness and accuracy of the formula and described the parameter variation before and after conversion qualitatively and quantitatively.