Most of the oil and gas reservoirs occur in marine carbonate strata in the Sichuan Basin. Recently, both PetroChina and SINOPEC have made great progress in exploring oil in this area. By analysis of source rocks, reservoirs, caprocks, traps and preserve factors, the paper believed that there are five sets of source rocks developed for hydrocarbon, namely, the first and third segments of Middle-Triassic Leikoupo Formation, the second and third segments of Lower-Triassic Jialingjiang Formation, the third segment of Lower-Triassic Feixianguan Formation, Permian Changxing Formation, and Maokou and Qixia Formations. Except the area around the foreland Tongtian fault and Lower-Triassic gypsum weathering area, the other sequences are all in good condition and regional structures are well developed in marine sediments, which has equipped with precondition for medium- or large-scale oil fields. Combined with potential evaluation and reservoir mode for marine sediments, the paper believed there is some prospect for increasing reserve of oil in South Sichuan. With the risks evaluation, the paper pointed out that different strategy of exploration should be adopted. In the piedmontsfront of Longmen Mountain, seismic collection, disposal and interpretation should be enhanced in order to find traps exactly. And in the Xiaoxinhe-Fenggu area, a compound exploration method should be taken and a risk drilling hole should be deployed at a proper position around the convergent area of structure zone and lithology.