Abstract: The discovery of Yancheng natural gas accumulation is tortuous and enlightening. The analysis on the basic geochemical characteristics of natural gas accumulation, the types of natural gas and its source rocks, and the maturity of natural gas shows that Yancheng natural gas accumulation is a type of "Paleozoic-generating and Cenozoic-reserving" late-accumulating one. This discovery provides a geologic model for the exploration of "Paleozoic-generating and Cenozoic-reserving" and "Paleozoic-generating and Mesozoic-reserving" typed natural gas accumulation in North Jiangsu area. It can also be used for reference in the exploration of the Meso-Paleozoic marine strata in Yangtze area.