An embodiment of the invention discloses a power grid statistics data derivation calculating method and a power grid statistics data deviation system based on a hierarchical storage model. The method and the system are used for settling technical problems of high artificial maintenance workload and easy omission through an artificial definition formula method, frequent modification and testing to a data processing module and stable system operation incapability in a special statistics calculation method by means of a special program. The method provided by the embodiment comprises the steps of constructing a power grid hierarchical relation model according to acquired power grid model data; defining and generating a universal calculation formula according to the power grid hierarchical relation model, wherein the universal calculation formula comprises a calculation factor, a result factor and a calculation logic; acquiring all records of an associated list domain of the calculation factor, performing deviation calculation on all the records according to the calculation logic, and writing an obtained calculation result into a model data position which is associated with the result factor.