Abstract: Ba sed on the study of the test pressu redata,the acoustic time and the recon strction of paleo-formation pressure,through the study of abnormal pressure in the middle and western Sichuan basin,it's shown that the distribution of stratum pressure differs greatly in different zones;the evolution history of paleo-formation pressure has been restored according to the models of the evolution history of pressure, and it shows that there were two high pressure a rouse,the firsta rouse in later Jurassic and the second in erlier Triassic,analyzing the relations between the excessive pressure distribution and the petroleum migration.