Abstract: Pulse YAG laser welding was used for the welding of stainless steel. The stability of welding process was studied based on the structure-borne acoustic emission (AE) signals released by the interaction effect of laser heat source and materials researched, which was characterized by scatters feature distribution of average peak-AE count. The result showed that the scatters distribution aggregation of average peak-AE count feature distribution was better as the process of pulse laser welding was stable. Conversely, the scatters distribution aggregation was more divergent. With the increase of laser pulse peak power, the average peak and AE counts of laser pulse AE event increased, which indicated that the AE count was more sensitive to the stability fluctuation of welding process induced by the laser pulse peak power. Consequently, it was possible to characterize the stability of laser welding process by the methodology of scatters feature distribution of average peak-AE count.