The PID control and the minimum control are both sensitive to system parameters. For a system as the hydro-generating unit with a parameter variability and non-minimum phase, the above-mentioned two kinds of control are difficult to achieve satisfactory control performance. But based on PID control process of data mining, using the regress function in MATLAB can obtain the linear analytical formula of the controller.This polynomial equation contains a PID control law as well as the characteristics of not sensitive to the system parameters, and has shown strong robustness when applied in the speed control system of hydro-generating unit.