Abstract：The dolomite reservoir of Huanglong Formation of Upper Carboniferous is one of the most important natural gas reservoirs in Eastern Sichuan-Northern Chongqing area. Based on the lithology characteristics of dolomites and combined with the palaeogeographical setting of the study area, four kinds of dolomite types：the penecontemporaneous dolostone，the diagenetic burial dolostone，the fresh water dolomite of epidiagenesis and hydrothermal dolomite of late diagenetic stage have been recognized. The burial diagenetic dolostone with diagenetic metasomatic geneses only are of reservoir significance，including two main rock types of grain dolostone and crystalline dolostone. By the synthetical analysis of geochemical characteristics of rare earth elements，it is recognized that different diagenetic dolostones are of various REE geochemistry characteristic and REE distribution patterns. This differences are connected with diagenetic liquid and physical chemistry characteristics of different phases，the features are as follows：①the penecontemporaneous dolostone and the burial diagenetic dolostone were much affected by karstification of epidiagenetic stage，and the slightly corroded dolostones and the strong corroded dolostones respectively has similar REE geochemical characteristic；②the fresh water dolomite of epidiagenesis has lower ΣREE，weak Ce negative anomaly and moderate-strong Eu negative anomaly；③the hydrothermal dolomite of late diagenetic stage were affected mainly by deep hydrothermal liquid，which has similar REE geochemistry characteristic with the fresh water dolomite of epidiagenesis.