Abstract: Based on core observation, thin section identification, diagenetic porosity evolution and studies of burial history relationship, the authors analyzed the origin and evolution of gypsum- salt rock microfacies of Leikoupo Formation in central Sichuan basin and investigated the controlling role and influence of gypsum-salt rocks on the reservoir of Leikoupo Formation in the aspects of sedimentary facies, diagenetic process, and tectonization. It is shown that the gypsum- salt rocks in central Sichuan basin were formed in a limited tidal flat environment of epicontinental sea, which included gypsum-halite pond of supratidal zone, gypsum- halite lake of intertidal zone and gypsum- halite basin microfacies of limited subtidal zone. Its origin included the concentration of the supratidal zone shallow dense brine in low areas, and the sinking and replacement of superficial dense brine produced in the intertidal-subtidal zone. The distribution of gypsum-salt rocks was related to the deposit center migration resulting from rising and falling of the sea level, and also had something to do with the distribution of the point beach. The formation of gypsum- salt rocks, the dissolution effects in the contemporaneous-penecontemporary period, the supergene period karst collapse and the medium-deep burial period dissolution generated by thermochemical sulfate reduction (TSR) all had important contribution to the formation and control of the upper reservoir in Leikoupo Formation in central Sichuan basin. In addition, gypsum-salt rock diapir as cracks and fractures generated by tectonic movements played a certain role in promoting the migration of hydrocarbon source and the redistribution of the gas reservoir.