At present, codes of practice rely on the single-silo seismic calculation to assess the seismic performance of the column-supported concrete group silos structure (CSCGSS). It is unreasonable proved by the work given in this paper. To more accurately calculate the earthquake action of a CSCGSS, the dynamic model of the overall structure considering the effect of dynamical coupling between different single silo in group silos is established for the first time. More in detail, based on linear elastic theory and multiple-degrees of freedom system motion, the model is used to analyze the base shear of CSCGSS with different storage mass conditions. Moreover, the computational model and the finite model are validated as reasonable through a shaking table test. Finally, the traditional vibration displacement superposition method for the single silo is updated to calculate the seismic action of the CSCGSS by defining the base shear force distribution coefficient to reflect the dynamical coupling effect in group silos. The results show that the frequency of CSCGSS decreases with the increasing quality of the stored material. Compared with the independent single silo, the base shear of group silos is uniformly distributed to different single silos under earthquake, but its value is not a simple superposition composed of the single silo. The base shear distribution coefficient acquired in the case of the empty, half, and full condition is tabulated and so a simplified calculation method is provided for engineers with a simple and accurate tool to estimate the seismic capacity of CSCGSS.