This work presents a trajectory tracking control method for snake robots. This method eliminates the influence of time-varying interferences on the body and reduces the offset error of a robot with a predetermined trajectory. The optimized line-of-sight (LOS) guidance strategy drives the robot's steering angle to maintain its anti-sideslip ability by predicting position errors and interferences. Then, the predictions of system parameters and viscous friction coefficients can compensate for the joint torque control input. The compensation is adopted to enhance the compatibility of a robot within ever-changing environments. Simulation and experimental outcomes show that our work can decrease the fluctuation peak of the tracking errors, reduce adjustment time, and improve accuracy.