The invention discloses a chemical poison occupational hazard risk grade evaluation method for petrochemical enterprises, and relates to the field of occupational health. The method includes the following steps of investigating and recording operating posts and corresponding operation types in a place to be evaluated, investigating and recording the working time, occupational exposure poisons, the working equipment airtight degree, working equipment operation time of workers and an engineering control measure corresponding to each operation type, determining the hazard grade and the exposure grade of each occupational exposure poison, obtaining the risk grade of each occupational exposure poison in each operation type and risk level grades of the corresponding operating posts according to the poison hazard grades, the poison exposure grades and risk grade evaluation rules, and making a risk evaluation report and a risk control and management report. According to the chemical poison occupational hazard risk grade evaluation method for the petrochemical enterprises, occupational disease prevention resources are used reasonably, the occupational health management efficiency is obviously improved, and the occupational health prevention and control cost of the petrochemical enterprises can be effectively reduced.