Abstract: In order to solve the problem of insufficient tracking accuracy of high precision electro optical tracking system (ETS) and to improve its ability to deal with uncertainty, a fuzzy sliding mode control method was designed first. The fuzzy logic control was used to adaptively adjust the switching term parameters of the sliding mode control (SMC) on line. Secondly, an interval type 2 fuzzy sliding mode control (IT2FSMC) method was designed to improve the ability of the system to deal with the uncertainty, and then to improve the tracking accuracy, so as to reduce the chattering of SMC. In addition, particle swarm optimization algorithm was used to ensure that the selected SMC parameters are relatively optimal. The proposed control methods were analyzed theoretically and compared experimentally. The results show that IT2FSMC can reduce SMC steady state error by 54.43% while reducing the chattering of SMC. Simulation and experimental analysis verify the effectiveness of the proposed control method in ETS.