On the basis of results of relative subjects, the fossil planation surface has been discussed by the authors from the point of geomorphologic view. The discussion contents included the characteristic information, research methods, paleotopography (gradient and altitude) and other problems about fossil planation surface. The recognition and reconstruction of fossil planation surface mainly rely on the following characteristic information: (i) the character of erosion unconformity surface; (ii) the paleo-weathering crust and residual deposits; (iii) the paleo-karst and filled deposit in the paleo-karst under the unconformity surface, and (iv) the character and environment of sediment above the unconformity surface. According to the above-mentioned characteristic information, the authors recognized and reconstructed two stages of fossil planation surface on Pa-leo-land of North China and Yangtze Paleo-land. These two fossil planation surfaces formed from Middle Ordovician to Lower Carboniferous and from Low On the basis of results of relative subjects, the fossil planation surface has been discussed by the authors from the point of geomorphologic view. The discussion contents incorporated the characteristic information, research methods, paleotopography (gradient and altitude) and other problems about fossil planation surface . The recognition and reconstruction of fossil planation surface mainly rely on the following characteristic information: (i) the character of erosion unconformity surface; (ii) the paleo-weathering crust and residual deposits; (iii) the paleo-karst and filled deposit in the paleo-karst under the unconformity surface, and (iv) the character and environment of sediment above the unconformity surface. According to the above-mentioned characteristic information, the authors recognized and reconstructed two stages of fossil planation surface on Pa-leo-land of North China and Yangtze Paleo-land. These two fossil planation surfaces formed from Middle Ordovician to Lower Carboni ferous and from Low