In an attempt to determine the main characteristics of vortex-induced motion (VIM) in a multi-column platform, this paper presents a numerical simulation of the VIM of a four-square-column platform under four spacing ratios using the turbulence model of the shear stress transport (SST k-ω). The coupling relationships among sway, surge, and yaw were investigated in motion response amplitude, frequency, and vortex flow patterns. The results indicated that the spacing ratio significantly influences the surge and it is affected by the spacing ratio is related to the reduced velocity. With increasing spacing ratio, surge amplitude gradually increases, while the main frequency shows a declining trend, characterized by a galloping-induced response. The sway and yaw motions are strongly coupled and unaffected by the spacing ratio, with their main frequencies constantly maintaining a 1:1 relationship; The sway frequency is also found to occur as an apparent lock-in phenomenon, and the natural frequency of the sway mainly controls the yaw motion. Furthermore, the results indicate that the sway motion of the four-square columns structure is likely to combine VIM and galloping.