In this paper, a fast terminal sliding mode control method based on finite time extended state observer is proposed for the two mass servo systems with unknown load position information. To estimate the unknown disturbances, a finite-time extended state observer is designed and incorporated into control design to compensate its. Then, combined with a new type of sliding mode reaching law, a nonsingular fast terminal sliding mode controller is proposed, which improves the reaching speed of sliding mode variables and ensures that the system state converges to the origin in finite time. The finite time stability of theclosed-loop control system is analyzed via Lyapunov stability theory. Comparative simulations and experiments are carried out based on a two-mass driving system to validate the efficacy of the proposed approach.