The invention discloses a modular design method of a nuclear power plant valve remote transmission device. The modular design method comprises the following steps that S1, the parts that make up the nuclear power plant valve remote transmission device are modularized, serialized design is carried out on each part module, and the remote transmission device and a valve port are solidified; S2, a corresponding series of parts are selected according to the nominal diameter and pressure rating of a valve and a path required by the remote transmission device; and S3, different assembly methods are designed for the selected parts according to different paths. The invention further discloses a modular nuclear power plant valve remote transmission device. According to the modular nuclear power plant valve remote transmission device and the modular design method of the modular nuclear power plant valve remote transmission device, the design of the valve remote transmission device is simplified,and a modular and serialized part library is set up and can be transplanted to other nuclear power projects as a standard component for selection of the design of valve remote transmission devices.