A simplified ‘Spring-Mass’ dynamic model and dynamic analysis were performed to obtain the influence of propellant consuming on the dynamic properties of a large scale satellite structure. Then the finite element modeling and analysis methods, including the beam modeling method, added with the mass method, the ‘RBE3-Mass’ modeling method and the virtual mass method, were given based on MSC.PATRAN/NASTRAN. In the end, the satellite finite element model was established and the dynamic analysis was executed. The analysis results indicate that: (1) the frequencies of main mode shapes will raise with the propellant consuming, while those of local shapes will not change ; (2)The frequency and magnitude of response will raise with the propellant consuming.