Abstract: The part working principle of electron prboe micro analyzer was briefly described. The influence of different test parameters of electron prboe micro analyzer on the mapping analysis results of Mg/Al alloy were studied, and the influence mechanism was analyzed. The results show that when there were hard convex precipitates on the surface of Mg alloy samples, the results were highly reliable when the same element used multiple crystals with different channels to collect signals at the same time. When the signal acquisition parameter of B element in the Al alloy was set to Peak/BG^-, the results were reliable but the efficiency was low, while when it was set to Peak, the efficiency was high but the results were unreliable occasionally.