The analysis of apatite fission tracks of 12 samples collected in Dongying Depressionindicates that the depression experienced a continuous cooling thermal history after its formation. Two distinct cooling processes took place during 50～60 Ma and 20～30 Ma respectly

and the cooling during 20～30Ma was resulted from the uplift and erosion of the depressionin the end of Dongying Formation

and the estimated thickness of the uplift and erosionamounts to more than 200 m. The depth of apatite fission tracks annealing zone ranges from 2 000 m to 3 400 m

which is well consistent with the depth of oil generation window.At thesame time

the rapid increase of recent temperature due to burial depth led to the high temperature range of the annealing zone.