Through macro-and micro-observation of thin sections and rocks from more than ten wells in combination with geochemical characteristics, the authors made a detailed investigation into diagenetic types and characteristics and examined the relationship between the diagenesis and the evolution of reservoir space. The findings show that the diagenetic evolution process of reservoir in the Middle Triassic Leikoupo-43 Formation in Longgang-Yingshan area of central Sichuan Basin was complex, and during this process various diagenetic actions were developed, with the reservoir quality being clearly affected by the diagenesis.