The invention belongs to the technical field of high-speed rail ballastless track maintenance, and provides a high-speed rail ballastless track maintenance roadbed physical isolating method aiming at solving the technical problem in the existing high-speed rail ballastless track maintenance. A physical isolation is arranged between an uplink and a downlink, is 2.7m away from the centre of an operating line, and is 2.3m away from the centre of a maintenance line; the height of the physical isolation is 2.6m above the top surface of a sealing layer; a colour steel plate and steel wire mesh combined structure is adopted. Transverse isolating sealing fences are arranged at the positions, close to a tunnel entrance and a bridge head, of the physical isolation. The high-speed rail ballastless track maintenance roadbed physical isolating method can perform large-area treatment without affecting traffic efficiency; when the physical isolation is detached, local overall movement is adopted to detach from a distance, so that the construction time is shortened, and the construction efficiency is improved.