The model of the loader work device was made with PROE and imported into the PATRAN.Then the model was analyzed with the NASTRAN and the vibration mode of the different frequencies was obtained.The frequencies were compared to the excitation frequency;the stiffness of the institution should be adjusted against the natural frequency to avoid the resonance,if those frequencies were in the range of the force safety factor.The research laid the foundation of loader work device design,which cut down the cost of production effectively.