The invention discloses a master/slave executor switching control method and a master/slave executor switching control system for a nuclear power plant. The method mainly comprises the following steps of: A, receiving a mode selection instruction input by an operator and selecting a running mode of a redundancy executor according to the mode selection instruction; B, generating a running control instruction of the redundancy executor according to the running mode, and controlling the redundancy executor to execute corresponding operation according to the running control instruction; and C, receiving state feedback information sent by the redundancy executor and generating an adjustment instruction according to the state feedback information, and controlling configuration and/or switching of a master/slave executor of the redundancy executor according to the adjustment instruction. The switching of the master/slave executor of the nuclear power plant can be controlled concentratively by performing module standardization on a master/slave executor switching system without independent processing of special situations, so that the working load of operators is reduced and manmade errors during design are reduced.