The accumulation and destruction of hydrocarbon reservoirs is discussed in the paper. Based on chemical kinetics model of oil generation by organic matter, gas generation by organic and gas cracked by oil, hydrocarbon generation and evolution of main source rock in the Nanpanjiang basin was calculated. According to bitumen filling periods, inclusion enclave analysis and relationship between bitumen and cementing matter in different generations, the multi-stage process of oil reservoir formation and destruction were studied. From the oil reservoir evolution, it is concluded that oil-cracked gas is the main hydrocarbon in future exploration of the Nanpanjiang Basin. But, it is very difficult for middle-large gas pool to form and the gas potential needs detailed study in this basin, because of gas accumulation in a very early period and gas destruction through a much long geological time, particularly, much less possibility of oil-cracked gas preservation due to hugely thick degradation after Triassic deposition.