Based on the literatures and the existent researches, the study on segment joint of prestressed concrete lining has been carried out. The analytical solution for calculating the rotational angle of the joint are deduced with the calculation assumption. So the rotating stiffness of joint is obtained. Compared with the experimental results, the numerical calculation suggests that the theoretical equations are reliable. Study shows the slip length of prestressing steel strand near the joint is one key to calculate the rotational angle and rotating stiffness of joint. The matched curve of the slip length with joint bending moment is given in the paper, which can be described by logarithmic function. When the rotational angle of the joint is calculated, the slip length could be regarded as a constant to simplify the calculation.