The Sinian Dengying Formation in the northern China, especially Sichuan Basin is a frontier for exploration of high evolution natural gas. Taking the Central Guizhou Uplift as an example, we found hydrothermal dolomitization and discussed the effect on reservoir development. Some dolomites, quartz and bitumen were found filled in dissolution caves or tectonic fractures in the Sinian Dengying Formation dolostones in the Central Guizhou Uplift. The coarse filling hydrothermal dolomites(HD)have features of curved crystal surface and wave extinction. Homogenization temperatures of fluid inclusions in HDs of different area are between 157.5 ℃ and 205.8 ℃, and the highest is 253.5 ℃. The oxygen isotope composition of the HDs is relatively light, and the δ18 OPDB values are between -15.3‰ and -8.6‰ and -11.2‰ in average. The87 Sr/86Sr values of the HDs are relatively high, ranging from 0.709 445 to 0.713 131, and 0.710 843 in average. The HDs have a typical feature of Eu positive anomaly in REE composition. The δEu values are between 1.11 and 7.46, and 2.37 in average. The hydrothermal activities have also dissolved the dolomites filled in caves or fractures, and some bitumen can be found in the dissolution pores. The hydrothermal dissolution and alteration are very significant for development of the Sinian and Lower Paleozoic carbonate reservoir beds in the north area of China.