Fuzzy immune PID was used to adjust the liquid-level of the starch production line based on the analysis and comparison of the principle of tradition PID, Smith prediction PID and fuzzy immune PID and a mathematical model about one of liquid-level loop of starch production line was built, then these three controllers were designed and simulated. The simulation results showed that the fuzzy immune PID is better than tradition PID in respect of control effect and its robustness is higher than Smith prediction PID. In the end, DDE protocol and ActiveX of Matlab were adopted to realize data exchange with RSView32 of the starch production line and transmit accurately the algorithm of fuzzy immune PID to RSView32.