The invention relates to a current fault component-based substation area backup protection method and system. The method comprises the following steps: 1) a substation area backup protection boundarycondition is determined; 2) differential areas with a boundary differential area and a component differential area covering different protection ranges are determined; and 3) substation area backup protection recognizes a fault position according to defined differential judgment of each differential area, and the original main protection action condition of the component, a power grid topology structure and a breaking state of a circuit breaker are integrated to realize high-performance backup protection for the substation. According to the current fault component-based substation area backupprotection method, various different types of fault in intra-station and inter-station lines can be quickly and reliably recognized, a tripping area can be expanded automatically when the circuit breaker fails to operate, the fault positioning time can be effectively shortened in the current fault component-based search scheme, and the safety of the power grid can be greatly ensured.