Abstract: The thermal maturity index (TTI) was applied in well Puguang 2 to recover the burial and thermal histories of the northeastern Sichuan Basin. In this way, the thermal evolution of source rocks and the hydrocarbon generation and migration processes in the study area were discussed. The maturity of source rocks evolved until the end of Cretaceous. Source rocks in the Lower Cambrian gave birth to hydrocarbon only from the Late Permian to the Late Triassic. Source rocks from the Upper Ordovician to the Lower Silurian gave birth to hydrocarbon rapidly from the Middle Triassic to the Late Triassic and also during the Middle Jurassic. Source rocks in Permian gave birth to hydrocarbon rapidly during the Late Triassic and the Middle Jurassic. All the above-mentioned source rocks experienced at least 2 hydrocarbon generation peaks, including the oil (liquid hydrocarbon) generation during the mature stage and the cracking of liquid hydrocarbon to gas during the high-mature stage.