Abstract: In order to study the influence of partially isolation on the dynamic characteristics and seismic performance， taking a dominate large terminal airport as a research object， a 3 dimensional finite element model using ABAQUS software is established. Based on this model， the structural vertical vibration modes， the effective mode mass， the vertical vibration acceleration， vertical deformation， component ductility， plastic damage and residual deformation are analyzed to reveal the influence of partially isolation on the dynamic characteristics and seismic performance. It’s demonstrated that partial isolation changes the vibration modes， increases the effective mode mass and magnify the vertical seismic load of the terminal building. At the same time， partial isolation filters the high frequency vibration， enlarges the low frequency vibration near the isolation frequency and increases the vertical acceleration and deformation. The plastic damage and residual deformation has been concentrated on the middle and end sections of inner-span beams.