On the basis of ever built vibration isolation dynamic model, dynamic equations, and decoupling analysis, the vibration problem of LFQ refrigeration system engine has been focused on. In addition, simulation models of current support mode and the half decoupling support mode for the engine vibration isolation system were established with ADAMS10.0, and linear modal analysis has been given. The result indicated that current engine support mode has severe vibration coupling, dynamic responses of mass center of the engine could decrease dramatically by the half decoupling support mode. Direction X and Y decreased to 0.79811 mm and 1.6095 mm, the problem of engine vibration coupling has been resolved by way of vibration modal analysis and simulation analysis of the dynamic response by I-DEAS8-0. The maximum deformation was 1.08 mm at the natural frequency 54.6 Hz (four mode shapes) of frame structure; the total structure rigidity is not ideal. The maximum deformation was 0.359 mm at the natural frequency 129.5 Hz by structural improvement, dynamic performance increased greatly.