The high order MQAM (multiple quadrature amplitude modulation) signals are analyzed by the ALRT (average likelihood ratio test) algorithm in aeronautical communication. It proposes a ALRT algorithm based on the receive diversity technique, and progresses the recognition performance. The simulation results show that, the recognition performance of ALRT algorithm based on the receive diversity technique is better in taxi scenario. Susceptible to signal to noise than channel and the fading of the 16QAM signal modulation recognition performance is also greatly improved, in addition, when the signaltonoise ratio over 10 dB, based on the ALRT algorithm for multi antenna diversity reception MQAM signal the correct recognition rate basically reached 100%.