A computer control system utilizing mathematical formula processing and more broadly knowledge engineering is characterized by a man-machine processing unit for defining a mathematical formula model, a program generation unit for converting the defined mathematical formula model to an intermediate code program, a storage device for storing usage conditions (rules) of the defined mathematical formula models and a unit for selecting a mathematical formula model which meets the stored usage condition based on data from a control unit of a plant under control, selecting a program corresponding to the selected mathematical formula model from the programs generated by the program generation unit, and supplying an operation result by the selected program to the control unit.
