Abstract: Aimed at the related factors influencing the abnormal flight events, based on the rough set theory, data rules were extracted by using software Rosetta, and the relationship between specific cause and the delay level of the flight delay was determined. Example analysis shows that under the incomplete and uncertain information condition, when some kinds of delay events occur, the final flight delay level can be predicted with the proposed method, which can help to prepare for starting safety early-warning in advance, and avoid clashes and excessive damage.