Based on the results of outcrop geological survey, core and slice observation, geochemical analysis, and reservoir simulation experiment, the lithofacies paleogeography, and the characteristics, origin, distribution of dolomite reservoir of the Cambrian Longwangmiao Formation in Sichuan Basin are analyzed. As a result, five conclusions are drawn: (1) The Cambrian Longwangmiao Formation could be divided into upper and lower sections in the Sichuan Basin, recording the climate change from humid to arid. In addition, the carbonate distally steepened ramp sedimentary models were established. (2) The granular shoals, the developing basis of the dolomite reservoir, are mainly distributed in the shallow ramp of the upper section of the Longwangmiao Formation. (3) Moreover, the contemporaneous dissolution, controlled by the exposure surface, is a critical factor for the development of granular shoal reservoir in the Longwangmiao Formation. (4) The dissolution vugs are not only extensively distributed, but also successively developed along the contemporaneous pore zones. (5) The granular shoals are superimposed in many stages in Yanting-Anyue-Weiyuan area, which are located in the high part of paleogeomorphology and developed buried dissolution, so it is a favorable area for exploration. Moreover, the granular shoals widely distributed in the whole basin are the potential exploration targets.