With the progress of Chinamade large aircraft and natural icing flight test in recent years, aircraft icing which is dangerous for flight safety, catches more and more attentions from both aviation and meteorology sectors now. Based on atmospheric temperature and humidity stratification profile, an improved icing potential algorithm with high probability of detection (POD), low false alarms ratio (FAR), easy application and practicability, is introduced in this article. The algorithm is verified and evaluated against 26 flight test/pilot reports. It is found that the diagnosed icing potential has high accordance with aircraft observation, and can give the approximate icing height and area in multiple weather conditions. By combing surface observation, radiosonde and satellite data, the algorithm is also verified in an aircraft natural icing observation experiment in Anqing, and the result shows that the algorithm can diagnose the particular height of icing level as well as the production and consumption of supercooled water, which has high consistency with aircraft sounding.