In this paper, the techniques such as oil-gas maturity parameters characterization, inclusion microstructure observation, reser-voir bitumen testing and grain fluorescence are used to analyze oil and gas charging sequence and history in Huomatu structural belt. The study suggests that the oil in Huomatu structural belt comes from the source rocks of Tugulu group of Lower Cretaceous, whereas the gas from the coal-measure source rocks of Jurassic. There are two main stages of hydrocarbon accumulation in Huomatu structural belt: the first stage is about 10 Ma ago, dominated by charging of low maturity oil; the second stage is about 3 Ma ago, dominated by gas charging and ac-companied with higher maturity oil. Such an early oil and late gas charging and evolution pattern suffers late adjustment and reconstruction, with gas-invaded fractionation locally.