Understanding the hydrocarbon charge history and accumulation process is crucial to petroleum exploration in the Bongor Basin, Chad. The chronology of hydrocarbon accumulations in the buried-hill of the basin was investigated by using a suite of techniques including organic geochemistry, fluid inclusion, Fourier transform infrared (FT-IR) spectroscopy, apatite fission track analysis (AFTA) and thermal history modeling. The results indicate that in the Bongor Basin, Subzone B and Subzone R-P of the buried-hill belt contain two types of oil inclusions exhibiting yellow-green and blue-green fluorescence, representing different stages of hydrocarbon charging. Based on AFTA and tuff zircon fission track data, it is inferred that different buried-hill zones experienced two phases of primary hydrocarbon accumulation, both peaking during 75-65 million years. In Subzone B, a secondary hydrocarbon accumulation event occurred during the uplift and reworking stage since the Late Cretaceous, characterized by hydrocarbon adjustment and redistribution. Most hydrocarbons are hosted in structural fractures, with the adjustment phase occurring approximately 30 million years ago.