The invention discloses a plastic pipe surface ultra-finishing and polishing system which comprises a feeding device, a clamping and locating device and a measuring device. The clamping and locating device is located at the discharging end of the feeding device. The automatic feeding purpose is achieved through the feeding device; the clamping and locating device is adopted for localization, after grinding is finished and through the cooperation of a first clamping device and a second clamping device, a steel pipe can be rotated when clamped and can be measured by the measuring device at multiple angles, and vibration and shakes of the steel pipe are reduced; and a carrying board is arranged, so that the steel pipe is placed more stably and measured more accurately, errors are reduced, and the measuring effect of the steel pipe is better.