The invention belongs to the field of operation of information systems, and particularly relates to a method for establishing an operation mode model of an information system. According to the method, the model is established according to longitudinal divided layers and transverse divided domains, the operation mode that different layers express different particle sizes is adopted for the longitudinal divided layers, and in the longitudinal direction, five layer models are obtained through division according to the complexity of the information system of a power grid enterprise; in the transverse direction, according to an ER graph model and service types, different operation entities are obtained through division and connected according to operation relations; each longitudinal divided layer is composed of a transverse entity relation model which includes the operation entity, the operation relation, an operation attribute and an operations state. Through establishing the operation mode model, all the operation entities involved in the information system are comprehensively carded with an application system being a bus, and the model is related with the detailed application system of the power grid enterprise. The method is a necessary means for monitoring the operation state of the information system and estimating risks.