The embodiment of the invention provides an urban power grid reliability evaluation method taking power generation, power transmission and power distribution systems into integrated consideration. The method mainly comprises the following steps: first of all, an urban power grid is divided into a power transmission network layer, a high-voltage distribution network layer and an intermediate-voltage distribution network layer; according to data of a power transmission network, calculating a reliability index of the power transmission network layer by use of a set algorithm, and converting the reliability index at a bus of the power transmission network layer into a power supply of the high-voltage distribution network layer through an equivalent power supply mode; converting a reliability index of a terminal bus at the high-voltage distribution network layer into a power supply of the intermediate -voltage distribution network layer through an equivalent power supply mode; and according to data of the intermediate-voltage distribution network layer, calculating a reliability index of the intermediate-voltage distribution network layer by use of the set algorithm. The urban power grid integrated reliability evaluation method provided by the embodiment of the invention effectively avoids the defect of only individual reliability evaluation of a power transmission network or a power distribution network, takes influences exerted by the power transmission network on the power distribution network into integrated consideration, and can truly reflect the power reliability of a power system.