Abstract: Different from foreign countries, the marine carbonate rocks in China are featured by development in small craton block, old geologic age, deep burial depth, and strong transformation, and the theory and technology are faced with problems in the evaluation of oil and gas exploration potential in the intraplatform, intra-carbonate strata, platform margin and old strata in deep formations. By relying on the carbonate reservoir project of national oil and gas special projects during the 11^th and 13^th Five-Year Plan periods and CNPC Key Laboratory of Carbonate Reservoirs, the targeted theoretical and technological researches on carbonate reservoir have been conducted, and innovative understanding has been achieved in four aspects, including: (1) The rifts are generally developed in the intraplatform of small cratons and the geological knowledge of sedimentary differentiation promotes the expansion of exploration field from platform margin to the intraplatform; (2) The discovery of new types of intra-carbonate karst reservoir promotes the expansion of exploration field from the local buried hill to the broad intra-carbonate strata; (3) The deep carbonate reservoir is controlled by sedimentary facies, consolidating the large scale and predictability of reservoir, which understanding promotes the expansion of exploration field from shallow to deep formations; (4) The geological understanding of “ternary” reservoir controlling and distribution of the ancient microbial carbonate rocks promotes the expansion of new exploration fields in the Meso-Neoproterozoic and subsalt Cambrian. The above theoretical progress supports to fill the gap in the field of carbonate reservoir study at home and abroad, and is confirmed by the discovery of large oil and gas fields such as Tazhong, Lungu, Halahatang, Shunbei in Tarim Basin, and Puguang, Yuanba, and Anyue in Sichuan Basin.