According to the CCAR-25-R4 “Airworthiness Standards of Transport Category Airplanes”and FAA advisory AC25-7C“Flight Test Guide”,drawing on the flight test experiences of other planes, this paper analyses the flight test principle and impact factors of ground minimum control speed(VMCG ) in theory, and discusses the flight test technique and the risk alleviated method of VMCG.It can provide guidance for the VMCG flight test of the civil airplane.