The invention discloses a measurement system of stiffness and camber of a steel plate spring, and a compensating measurement method thereof. The system is characterized by comprising a horizontal reference table which is supported with a measured steel plate spring by pulleys positioned at the two ends; a compression bar which is positioned above the measured steel plate spring and at the centralposition of the measured steel plate spring, is vertically arranged and can move upwards and downwards, wherein, the bottom part of the compression bar can exert pressure on the measured steel plate spring by a pressure head; a pressure transducer which is used for measuring the pressure that is exerted by the compression bar on the measured steel plate spring by virtue of the pressure head; and a displacement transducer which is used for measuring the displacement of the pressure head in relation to the reference table. In the method and the system, the camber measurement error is compensated according to the linear relation between the elastic deformation and the pressure of the steel plate spring. A threshold pressure is preset so as to effectively reduce self zero output error and external interference errors of the transducer, and the errors resulting from the dead weight of a guide bar, the pressure head, the pressure transducer and the like.