The invention discloses an oil-immersed transformer status evaluation modeling method, which comprises the following steps: (1) building a data model of N: 1 relationship of a calculation factor layer, a mark deduction formula layer, a component classification layer and a device layer in sequence according to the status variable mark deduction standard of an oil-immersed transformer; and (2) judging whether a mark deducting formula works according to a calculation factor, counting and accumulating the deducted marks of a component according to the mark deducting formula, analyzing the status level of the component according to the deducted marks of the component, and taking a device status level as the maximum value of the status level of the component. The invention further provides a transformer evaluation system. According to the method, classified and layer modeling is performed on a given oil-immersed transformer status variable mark-deducting standard, calculation and counting are performed from a low layer to a high layer, and the status level of the transformer is evaluated according to the marks deducted by classification so as to provide the basis for the status maintenance of the transformer and improve the running stability and reliability of a power grid.