The invention relates to the technical field of constructional engineering, in particular to a monitoring and measuring method for an underground excavation section of a subway station in a dense building area. Vault subsidence, clearance convergence in a hole, ground surface subsidence, underground water level, vertical displacement of a bottom plate, vertical displacement of buildings, inclination, cracks, pipeline subsidence and supporting axial force are monitored on a construction site. Compared with the prior art, the advantages are as follows: the invention provides a monitoring and measuring method for an underground excavation section of a subway station in a dense building area, which realizes whole-process monitoring of ground buildings and the excavation working face of a subway body station and reduces the adverse factors and risks in construction; and the initial state of the construction site is inspected before construction, the construction site is daily inspected after construction is started, and defect positions and parameters recorded each time and site images of the defect positions are comparatively observed so as to discover adverse factors and risks in construction in time.