ue to the role of gas force, scroll plate with different involute profile will be deformed, affecting the efficiency of the machine.In order to study the deformation of the scroll plate with variable radius circle involute profile, ANSYS finite element analysis software was used to simulate its stress distribution and deformation state which were compared with those of the scroll with fixed radius circle involute profile under the action of gas force. The analysis shows that the use of the scroll plate with variable radius circle involute profile can effectively reduce the amount of deformation and the leak of the expander, which can improve the efficiency of the expander, and the structure is more compact.