The invention discloses an anti-deflection structure of a machine cover inner plate. The anti-deflection structure of the machine cover inner plate is characterized in that an inward concave reinforcing groove is formed in the side wall of the bag surface on the air window side of the machine cover inner plate; and 6-10 protrusions are arranged on the reinforcing groove at intervals. The rigidityof the machine cover inner plate is effectively improved, the problem of deflection deformation of the assembly is effectively solved, a good foundation is laid for the quality improvement of a stamping part, the debugging shift is reduced, and the production cost is saved.