Flight safety is not only the basis of all flight activities, but also the lifeline of flight. In a particular case, how to guide the aircraft to alternate base landing is a realistic problem facing pilot. The reasons of the aircraft forced landing is in-depth analyzed, and makes specific analysis to how to choose the reasonable alternate base, and summarizes the principle of selecting alternate base to be followed, also proposing a correct solution. The research provides a certain reference significance and positive realistic significance to guide the aircraft to alternate base landing, ensuring flight safety and directing flight training in special conditions.