The invention provides an adjustment system with the post-pressure of an air compressor as control pressure in the technical field of an internal combustion engine, comprising an air compressor, a turbo, an engine, connection pipes, a volume chamber, a moving body, a penetration pipe and an elastic part, wherein two ends of the first connection pipe are communicated with an exhaust pipe and the upper wall face of the volume chamber respectively; two ends of the third connection pipe are communicated with the right wall face of the volume chamber and the air inlet pipe of the engine respectively; and the penetration pipe penetrates through the upper wall and the lower wall of the moving body. During the working process of the engine, the moving body can move left and right in the volume chamber; under the low speed working condition, since the pressure on the right side of the moving body is lower, the moving body moves rightward; the first connection pipe and the second connection pipe cannot be communicated; the air inflow of the engine is relatively increased; and the power rises. Under the high speed working condition, since the pressure on the right side of the moving body is higher, the moving body moves leftward; the first connection pipe and the second connection pipe are communicated with each other; the air input of the engine is relatively decreased; and the explosive pressure of each cylinder is decreased. The adjustment system with the post-pressure of the air compressor as the control pressure is rational in design, simple in structure and applicable for a turbo charging system of the engine.