Aiming at the problems such as high frequency of airspeed anomalies, multiple fault types, great impact on flight safety, and heavy burden of pilots’ disposal after airspeed anomalies, this paper designed an auxiliary decision-making function for airspeed anomalies of large aircraft. Under different flight phases and aircraft performance, the residual voting judgment, flight status conformity judgment, airspeed reconstruction algorithm based on wind speed and airspeed reconstruction algorithm based on lift equation are designed are respectively studied. Taking the DaYun large aircraft as an example, the simulation results show that the method is effective.