Abstract: In this paper,the authors describe the origins of nodular and vermicular limestones on the basis of lithologic characters,the both lateral and vertical distribution of their strato-horizons,the changes of lithofacies and paleogeography.It is suggested that the nodular limestones are the typical product on the lower slope section of platform margin and derived from the diagenesis of gliding clasts.Therefore,the nodular limestones could be good reservoir rocks.The vermicular limestone generally developed on the upper slope section of platform margin and their origin is rather complicated,part of them may be related to sedimentation and fragmentation.