The invention relates to a thin-wall cylindrical part cylindricity detecting device and a thin-wall cylindrical part cylindricity detecting method, and belongs to the technical field of cylindricity detection. An intermittent rotating table and an ascending and descending mechanism are in left and right arrangement and are both arranged on a work tabletop; the right end of an ascending and descending rod is arranged on an ascending and descending slide block of the ascending and descending mechanism; the right end of a connecting rod is detachably arranged on the left end of the ascending anddescending rod; the left end of the connecting rod is downwards bent; the bottom surface center of the left end of the connecting rod and the center of the intermittent rotating table are in coaxial arrangement; a non-contact type measuring device and a contact type measuring device are detachably arranged on the left end of the connecting rod; a first distance measuring sensor is arranged on theconnecting rod through a first support frame; and a thin-wall cylindrical part is detachably arranged on the intermittent rotating table through a clamp. The fixed measurement can be performed, so that the measurement is more precise; the measurement mode is simple; and the deformation of the thin-wall cylindrical part in the clamping and installing processes can be effectively avoided.