Accidental release of the hazardous gases with high release frequency, widely used in petroleum refining and chemical industries will cause serious effect.In order to obtain the key information to manage the hazardous gases release accident, a computational fluid dynamics (CFD) model was established to simulate the movement characteristics of released gas and the distribution of hazardous gas concentration in time and space after release.The instantaneous release scenes from Thorney Islands Trails were used to validate the CFD model with the software Fluent.The result showed that the model could provide the information of the movement characteristics of the gas cloud and the distribution of hazardous gas concentration in time and space. Accidental release of the hazardous gases with high release frequency, widely used in petroleum refining and chemical industries will cause serious effect. In order to obtain the key information to manage the hazardous gases release accident, a computational fluid dynamics (CFD) model was established to simulate the movement characteristics of released gas and the distribution of hazardous gas concentration in time and space after release. instantaneous release scenes from Thorney Islands Trails were used to validate the CFD model with the software Fluent. result result that the model could provide the information of the movement characteristics of the gas cloud and the distribution of hazardous gas concentration in time and space.