Abstract: In this paper, the process of hydrocarbon generation and evolution in the four thermal evolutionary stages (low-mature, mature, high-mature, overmature) of geohistory is simulated by selecting low-mature hydrocarbon source rocks and using the method in which hydrocarbons are generated from artificial pyrolysis and petroleum migration is controlled properly. In the experiment, the hydrocarbons generated from pyrolysis are appropriately classified as drained and occluded hydrocarbons which correspond to the amount of hydrocarbons in geologic body entering reservoirs by primary migration and the amount occluded in parent rocks and evolving continuously together with parent rocks, respectively. The generation of hydrocarbons can be divided into four stages with continuous evolution, from unmature to overmature stages, and the migration into three concentrated stages; that is, the geological process of geologic body during which hydrocarbons generate and migrate simultaneously is simulated as multistage generation and concentrated migration, Thus, the possible distribution of hydrocarbons in reservoirs in different evolutionary stages and under different migration efficiency can be obtained.