The invention discloses an optimizing method of an automatic control system for sealing performance detection of a diving suit, and relates to the field of quality detection of diving suits. The method is characterized in that the input ideal piston position in a cylinder is compared with the actual piston position detected by a displacement sensor, and a difference signal is calculated by a PLC through a control algorithm and then is processed by a power amplifier to obtain a simulation signal; an electric proportional valve is controlled through the simulation signal, and the electric proportional valve controls the cylinder to enable the moving of a piston rod in the cylinder, and a clamping plate is driven to clamp the diving suit. According to the method, the pole point arrangement theory of the automatic control system for the sealing performance detection of the diving suit is utilized, and the state of the automatic control system for the sealing performance detection of the diving suit is fed back, and a state feedback matrix K of the control system is solved, and then the control system in an original state can be changed into an expected improved system from through thestate feedback matrix K.