The invention discloses a sphere inner hole milling and boring mechanism, which comprises a main shaft, a main shaft connecting sleeve is nested at the outside of the main shaft, a tool post disc is arranged at the front end of the main shaft, a tool post is connected in the tool post disc rotationally, a linkage mechanism is connected at the tail end of the tool post rotationally, and the other end of the linkage mechanism is fixedly connected with a circular sleeve, the rear end of the circular sleeve is connected with a feeding mechanism, the circular sleeve is nested on the main shaft connecting sleeve axially and glidingly, and rotates with the main shaft connecting sleeve by linkage. The sphere inner hole milling and boring mechanism can be arranged on rams and main shafts of commonfloor-type milling and boring machines and gantry type milling machines, and has relative low tool path error and spherical contour error when in uni-axial and co-diametric tool feeding; and the invention takes the rotation of the sphere main shaft as the main motion, and the feeding mechanism realizes the auxiliary motion, the combination of the motions improves the boring efficiency, the spherical surface precision is up to standard, the machine tool utilization rate is increased, the production loads of high-precision machine tools are released, and the input costs of equipment are greatlysaved.