The invention discloses a system and a method for comprehensively grading and characterizing the safety level of a refinery enterprise, and belongs to the technical field of safety production evaluation of the refinery enterprise. The representation system comprises a client, an evaluation parameter configuration module, an evaluation calculation method configuration module and an evaluation report module, wherein the evaluation parameter configuration module, the evaluation calculation method configuration module and the evaluation report module are all in communication connection with the client. The method comprises the following steps: firstly, selecting a refining enterprise to be developed, selecting an evaluated refining device facility unit from the selected refining enterprise, further obtaining a safety level score of a device facility, and obtaining a safety management level score of the device facility; and calculating the safety level comprehensive grade of the refining enterprise according to a formula. According to the method, the technical level and the management level of the enterprise can be effectively combined, and the safety management level of the enterpriseis comprehensively characterized, so that the safety level of the refined enterprise can be more scientifically characterized from two dimensions of technology and management.