The maneuvering load is significantly correlated with the pilot's operation, thus indicating the maneuvering motion of the aero-engine during the actual flight. Accordingly, the establishment of accurate distribution models is of great engineering significance and high theoretical value for the compilation of load spectrum. In this paper, to analyzing the statistics of the normal overload coefficient (NOC) spectrum of aero-engine, a mixed distribution model is built in accordance with the Peak Over Threshold (POT) model. A threshold selection method relating to usage is proposed based on the correlation between the rotating speed and the normal overload coefficient. The normal overload coefficient data which is higher than the threshold is defined as extreme load, while the normal overload coefficient data which is lower than the threshold is defined as medium–low load. The multi-correlation coefficient between the model fitting distribution curve and the measured normal overload coefficient distribution curve lays a basis for judging. As revealed by the results, the measured normal overload coefficient finds good agreement with the mixed distribution model.