Abstract: Wutan-1 well is the only risk well in eastern Sichuan to drill Cambrian and Sinian strata. It is of great significance to study the reservoir forming by analyzing the fluid inclusion characteristics of the reservoir in Longwangmiao formation of Cambrian, so as to clarify the exploration potential of lower Paleozoic natural gas in East Sichuan. The host mineral of fluid inclusions in the Longwangmiao formation of Wutan-1 well is dolomite, which has two stages of development characteristics, corresponding to Silurian-Devonian initial hydrocarbon generation stage and Devonian Middle-Triassic paleo reservoir formation stage respectively. The homogenization temperature of inclusions is less than 180 ℃, lacking of late cracking gas generation period and adjustment of filling period. According to the analysis of comprehensive preservation conditions, the Cambrian gas bearing property of Wutan-1 well is poor, but it is beneficial to the migration and accumulation of natural gas to the overlying medium shallow layer, which is the next exploration direction in this area.