Abstract The Micromanipulator for surgical robot always with small size，the space of the end is narrow， It is difficult to install angle sensor in the end, closed loop control of the joint angle could not be achieved, A new closed loop control method based on joint angle estimator was presented for this problem. The joint angle estimator is based on the dynamics analysis of the cable-driven system, a new driving scheme for micromanipulator was designed, and a single joint principle prototype experiment system was established. The parameters of joint angle estimator were given through the method of dynamic parameter identification. What’s more the simplified and modified models were achieved. The experiment results shown that the precision of the joint angle estimator can reach to 0.38deg. At last the position closed-loop control experiment of the joint angle was researched through the method of regarding the joint angle estimator output as the feedback signal. The results showed that the maximum follow error is about 0.734deg. The precision of joint angle closed-loop control reached to a high level.