Precision is the main factor limiting the development of serpentine space robot,which is made up of modular joints with the same structure and shows for dexterity in small spaces.In order to improve the position accuracy and guide the precision design of the serpentine space manipulator,a regularized kinematic calibration method for a single 2-DOF joint was proposed.A matrix total differential theory error model comprising all geometric error parameters was constructed based on the kinematics analysis of the 2-DOF joint with multiple mapping relations,and the sensitivity analysis of all 2-DOF joint error sources was conducted.The 3σ principle and the ideal position accuracy design index served as the guidelines for each components tolerance design.Finally,the regularization method was used to identify the errors of the 2-DOF joint,which was used to compensate for the nominal kinematic model in the controller,after accounting for all manufacturing and assembly errors.The results showed that the modified kinematic model’s position accuracy was improved by 50% and proved the validity of the kinematic calibration.