Abstract: Under the strong lift and strata erossion in Himalayan movement, most part of central Shichuan area lacks upper Jurassic and the above strata. According to the analyse of mudstone interval transit times from typical wells in Bajiaochang gas field and Nanchong gas field, the eroded strata is about 2500 metres in thickness. On the basis of the strata compaction correction of different rocks, history of Xiangxi group in upper Trassic and thermal evolution history of hydrocarbon has been reconstructed in 163 wells by basin modelling. The results show that source rock of Xiangxi group in upper Trassic got into hydrocarbon generation threshould (Ro=0.5%) at the end of middle Jurassic, and reached lowmature stage in later Jurassic(Ro=0.5%～0.7%). The peak of hydrocarbon generation took place in Cretaceous.To the later Cretaceous ,most part of Central Shichuan Area were in the fastigium of hydrocarbon generation,except northern area of central Shichuan where highmature later stage(Ro=1.3%～2.0%). Since Paleogene, Strata uplifting and erossion has resulted in strata temperature loeing down which preventes hydrocarbon of source rock from further generation.

Key words: upper trassic, source rock, thermal evolution history, burial history, hydrocarbon generation history, Central Shichuan Area