Abstract: A new pattern of structures, combined isolation structure, was presented, and its vibration and control equations were derived. Based on the hypothesis that the input for earthquakes is white noise and using the principle of random optimal control, the features of vibration control and the effects of parameters such as isolation degree, damping and ground site on themwere analyzed. The research result indicates that the vibration control system of combined isolation structures can bring the seismic responses of structures under effective control by optimixing control parameters.