According to one embodiment, a plant control system includes a station mounting controllers thereon, an engineering device which manages programs, and a device which connects the controllers and the engineering device. The engineering device includes database which stores information on a first variable for allowing data to be shared among programs in each controller and a second variable for allowing data to be shared among programs in the station, the database management part, and a relocate management part which moves the program, and the relocate management part includes a designating module which designates an execution order of programs in a source controller, one or more programs to be moved, a destination controller, and the source controller, a module which moves the program as designated in the designating module, and a changing module which, when the program is moved, moves or copies the first and second variable used in the program.