The invention concretely relates to a static reliability assessment method for a power transmission network. The method comprises the following steps of: (1) establishing a topological analysis model for reliability assessment of the power transmission network and determining assessment parameters; (2) establishing a connected set matrix of the topological analysis model; (3) comparing a connected set number i between a substation required to be calculated and an adjacent substation with a connected set number j between every two adjacent substations, and calculating reliability data of a loop between every two substations; (4) determining a reliability index; and (5) analyzing the reliable performance of a power transmission network system according to the index determined in the step (4). The method provided by the invention can be used for rapidly assessing the reliability level of the power transmission network system by means of the topological analysis model of the power transmission network system and is simple in calculation; a convenient and rapid reliability index calculating method is provided for operating and planning personnel when a planning and operating scheme is repeatedly modified and corrected; and the method is simple, rapid and intuitive in calculation and has higher practical guiding significance and application value.