Abstract: We divide the system into first and second order subsystems by linear transformation,and next derive an analytic relation between weighted matrix Q of the systemand closed-loop poles by means of the relations between the weighted matrix Q of subsystems and system parameters.The relation between the optimal feed matrix K and closed-loop poles is further derived.Trial-and-error methods are thus avoided insystem design.While using the method to multivariable system design we obtain anew effective method for this purpose.The application results of the method in DC regulating-speed system design haveproved its effectiveness in engineering design.