The invention discloses a relaying control method for a long-stator linear synchronous motor. The method comprises that: 1, a propulsion control system of an nth subarea fully controls a long stator, the propulsion control system of an (n+1)th subarea is on standby, and the propulsion control systems of adjacent subareas perform data synchronization by utilizing a reflective memory network; 2, the propulsion control system of the nth subarea half controls the long stator, and the propulsion control system of the (n+1)th subarea serves as an assistant; 3, the propulsion control system of the nth subarea assists in controlling the long stator, and the propulsion control system of the (n+1)th subarea half controls the long stator; and 4, the propulsion control system of the nth subarea is on standby, and the propulsion control system of the (n+1)th subarea fully controls the long stator. In the method, communication is established by adopting the reflective memory network, high speed, high real-time performance, electromagnetic interference resistance and high accuracy are ensured; the adjacent subareas synchronize data to ensure the consistency of control in the adjacent subareas; and control power is transferred step by step so as to avoid the current of a frequency converter unit being fluctuated in the transfer, ensure the continuity of propulsion forces of the propulsion control systems, maintain the stable running of a rotor and improve the system reliability.