Abstract: Technical details of using acoustic emission for the real time monitoring of critical structures exerted by multi-load during aircraft landing gear fatigue test in the early stage were introduced. With respect to the complication of the AE signals, load-based filtering methods were employed to process the signals. After acquiring the processed AE signals, trend analysis was given priority for the diagnostic parameter, which was further verified by correlative parameter trend analysis. As an example, AE signals coming from the load affecting the critical part the most were processed and analyzed, and satisfactory result was obtained. Success was made in predicting the change of status of the loading system. These provided important guarantee for fulfillment of the main loading gear test.