The safety of marine structures and underwater vehicles is threatened by the internal solitary waves (ISWs). The experimental study of the load characteristics exerted by ISWs on an immersed square column has been carried out in a stratified fluid flume. A new type of submerged load measurement platform is proposed to measure the changes in load exerting on the square column, and an array of conductivity probes is used to obtain the characteristics of ISWs. The influence of wave-flow fields of ISWs and depth of square column on the load characteristics is comprehensively analyzed. The results show that the load on the square column is mainly determined by the ISW-induced flow field. The intensity and trend of the forces at different depths are different, and the intensity of forces increases with the increase of wave amplitude. Square column will experience roll and pitch when encountering ISWs during the diving process, with the pycnocline being the region with the strongest rolling and pitching.