Abstract: The safety of hazardous chemicals has been a vital challenge to human being for decades. Scientists and engineers have focused on the risk researches of those kinds of substance for years. Aiming at the hazardous factors and serious consequences of the potential accidents, a quantitative systematic methodology is developed for assessing the risk of the hazardous chemicals based on chemicals properties, producing and storing process, operation environment, and with the consideration of the safety management state of enterprises. The system formation of the methodology is analyzed.The mathematical models are established for each assessing process and parameter,and the accident damage models and consequence classification are put forward. It can be shown that the methodology has prospective engineering application value.