Considering the non-parallel bearing surface, the evolution mechanism of the connection stiffness of a superalloy bolted connection and its influence on the rotor modal were studied. The geometrical errors of the bolts and connect members were represented as the nonparallel deviation of bearing surface, and then the simulation model of tightening process and axial loading process were established. By changing the inclination angle of the bearing surface from 0 degree to 2 degrees, the mechanical properties of the bolted connection were analyzed, and the variation law of bolt tension and stress distribution under nonparallel contact was revealed. Furthermore, the modal analysis of the rotor with non-parallel bearing surface was conducted to find out the change rules of the rotor modal under nonuniform distributing connection stiffness. The results show that the nonparallel bearing surface mainly influences the highorder modes, and the corresponding mode shape dominated by the openingclosing movement of the bolted connection.