The invention provides an aligning and leveling worktable for measuring the cylindricity of a slewing type workpiece. The aligning and leveling worktable is composed of an aligning knob (1), an aligning supporting seat (2), an aligning sliding block (3), an aligning tension spring (4), an aligning fixed supporting seat (5), a bearing (6), an outer cover (7), a fixed steel ball (8), leveling knobs (9), a leveling knob supporting seat (10), an inclined block (11), a leveling tension spring (12), leveling steel balls (13), a leveling fixed supporting seat (14), a connecting ring (15), a base (16), a worktable (17) and a vertical tension spring (18). The leveling steel balls are movable supporting points, and the fixed steel ball is a fixed supporting point. The two leveling knobs are adjusted to lead the worktable to realize the leveling function under the support of the two leveling steel balls and the fixed steel ball. When the aligning knob is adjusted, the connecting ring drives the worktable to precisely move along two vertical directions under the action of the aligning tension spring so as to realize the aligning function of the worktable. The structure of the aligning and leveling worktable is simple and practical.