In recent years， modular architecture has developed rapidly in China， and the technical stamdard system has been graduallg established. A simplified equivalent frame calculation model of the modular unit with an ultra-high performance concrete （UHPC） core column was established based on the stiffness equivalence principle. Finite element calculations and experimental results， including the lateral cyclic loading tests and the pseudo dynamic tests， were compared and analyzed to verify the effectiveness of the model. Based on the proposed simplified model， the seismic performance of a six-story UHPC building structure was analyzed by Midas Gen. The calculation results show that the elastic deformation ability of the structure is excellent under frequent earthquakes， which meets the requirements of the fortification level of “no damage under frequent earthquakes”. Under the action of rare earthquakes， the damage is concentrated in the connecting of module units， and the structure remains upright after the earthquakes， which meets the requirements of the fortification level of “no collapse under rare earthquakes”.