Aiming at the problem of low intellectualization of program controlled unmanned aerial vehicle(UAV), intelligent correction method for flight control system based on online simulation system is proposed. Online state monitoring and anlysis, real-time updating of simulation model and other technologies are used. UAV online simulation system is designed to auxiliary controll UAV’s track correction and speed correction. Intelligence of UAV flight control is improved further. Through UAV mathematical model simulation system and simulation and test system of flight control system hardware in loop, experimental verification is conducted. The effective combination of intelligent correction technology and man in the loop control method is realized.