An integrated study is carried out by analyzing sedimentary and evolution history of the Sichuan Basin and various thermal evolution analytical data(such as vitrinite reflectance) of 188 core samples from Puguang-5 and other wells in northeastern Sichuan Basin.The results show that:1) palaeogeothermal restored by using vitrinite reflectance(VR

o

) or equivalent bitumen reflectance(BR

o

) and illite crystallinity can be used as good palaeo-geothermometers.It represents the maximum temperature that the strata underwent during effective heating time.The VR

o

or equivalent BR

o

shows exponential increase with paleotemperature increasing.Moreover

they also relatively increase along with the increasing effective heating time;2) homogenization temperature of fluid inclusion is the most direct palaeo-geothermometer for determination of paleotemperature and timing of hydrocarbon accumulation.The highest homogenization temperature of fluid inclusion is consistent with the paleotemperature recovered from vitrinite reflectance.It represents the highest palaeotemperature

and is also an effective index for timing of hydrocarbon accumulation and reconstruction of thermal histories of various stages;3) the closure temperature of apatite and zircon(U-Th)/He can also be used as geothermometer.Combined with dating

it can be applied to restore the thermal history of basin forming and orogenesis;4) therefore

for high mature marine sequences

the maximum paleo-burial depth

palaeogeothermal and thermal history can be restored according to VR

o

or equivalent Bro

highest homogenization temperature of fluid inclusion

illite crystallinity and closure temperature of apatite and zircon(U-Th)/He combined with dating.