The Puguang gas field recently discovered in the Sichuan basin is the largest and deepest gas pool, and of the greatest abundance in resource. Based on the course of exploration and discovery as well as the basic features of the field, the discovery of the field and its enlightenment for hydrocarbon prospecting have been summarized, that is, new thoughtways are needed for the exploration of mature basins, survey techniques are the guarantee for accelerating the exploration, and exploration risks can be effectively reduced by three-dimensional exploration for basins rich in hydrocarbon and with various types and complicate conditions of reservoir formation.