The invention relates to a municipal drainage pipe network diagnostic assessment method giving consideration to a key node. The method includes the following steps that (1) the key node of a municipal drainage pipe network is obtained, a water level monitor and a flow monitor are additionally arranged at the position of the key node, actual running water level and flow data of the key node are obtained, and on-site pipe data at the position of the key node are obtained through CCTV measurement; (2) in cooperation with the actual running water level and flow data, topological data of the drainage pipe network, the on-site pipe data, boundary water level data, GIS data, ground elevation data and other data of the key node, a municipal drainage pipe network hydraulic model giving consideration to the key node is built; and (3) calibration is carried out on the municipal drainage pipe network hydraulic model, the municipal drainage pipe network hydraulic model obtained after calibration is adopted for simulating the running state of an actual municipal drainage pipe network system, and the running state of the system is assessed. Compared with the prior art, the municipal drainage pipe network diagnostic assessment method has the beneficial effects of giving consideration to the key node, being accurate in modeling, capable of achieving combined assessment, real and effective, improving efficiency and the like.