In high-speed optical communication systems, in order to improve the communication rate, the distance between pulses must be compressed, which will cause the problem of the interaction between optical pulses in optical communication systems, which has been widely concerned by researches. In this paper, the bilinear method will be used to analyze the coupled high-order nonlinear Schrödinger equations and obtain their three-soliton solutions. Then, the influence of the relevant parameters in the three-soliton solution on the soliton inelastic interaction is studied. In addition, the constraint conditions of each parameter in the three-soliton solution are analyzed, the inelastic interaction properties of optical solitons under different parameter conditions are obtained, and the relevant laws of the inelastic interaction of solitons are studied. The results will have potential applications in the soliton control, all-optical switching and optical computing.