The carbonatite paleokarst rocks of Upper Carboniferous Huanglong Formation constitute one of the most important natural gas reservoirs in Linshui of eastern Sichuan-northern Chongqing area. Based on structural features of karst rocks, the authors have divided the karst rocks of Huanglong Formation into four types, namely slightly corroded karst rock, medium degree corroded and porous karst rocks, strongly corroded brecciated karst rocks and strongly corroded and altered secondary gray-karst rocks. Moreover, two types of cements of limnic calcite and limnic dolomite and hydrothermal dolomite of reburial period are included in the karst rocks. A synthetic analysis of geochemical characteristics of rare earth elements has led to the conclusion that karst rocks or cements of different rock textures, components and corrosion intensities obviously have different REE geochemical characteristics. It is thus thought that the migration, distribution, enrichment and abnormal effects of the REE can not only be used to distinguish fluid properties and paleo-hydrologic conditions but also serve as one of the important indicators for evaluating and forecasting paleokarst rock reservoirs.