The vehicle systems usually employ the passive damping device to dispose of an oscillation. In passive damper, it is important to choose the design parameters (the stiffness of spring and coefficient of damper) so that the oscillation target of vehicle is the best in the operating conditions (typical load mode, the working speed range, typical street). In this paper, the author proposes a solution to choose the design parameters based on a stochastic optimization algorithm which is assumed that this device is an active damper (the damping device is controlled by an electronic control system). According to design parameters of the passive damper are found by a covariance matrix and an equation order reduction. The results of proposed method are positive approach which is proven by the simulation results. Thereby, it will open a possibility for practical applications.