The invention relates to a method for evaluating information physical security risks in a power system. The method comprises the following steps: S1, randomly assuming that any one information cell in an information space fails due to a network attack; S2, according to connections between power cells and information cells, determining whether certain power cells fail; S3, if so, calculating a power system trend, and determining whether certain power cells exceed a limit at a next time point, and if not, waiting until simulation is carried out at the next time point; S4, according to state conversion rules between the power cells and the information cells, updating states of the information cells and the power cells at the next time point, and based on this, updating the system trend; and S5, counting the system scale of a power space. According to the invention, propagation of the information physical security risks between the power space and the information space can be displayed in a graphical manner and the information physical security risk level of the power system in the background of wide interaction between the power system and an information system can be evaluated.