Based on the study of outcrop and thin section observation, the distribution pattern of oolitic limestone and its ooid characteristics in the North China Plate are presented. Olitic limestones were widely distributed in the area during the Third Series of Cambrian. Generally, the oolitic limestone elevates in strata gradually from east to west, which indicates that the oolitic limestone is diachronous. In this background, the inner ramp ooid shoals developed in the central belt of the study area, with open sea in the east and shoal back tidal flat in the west.