A Sr0.95Al2O4:0.02Eu2+, 0.03Dy3+ phosphor was synthesized via co-precipitation with ultrasound assistance and subsequently sintering at 1 200 ℃for 3 h. The effect of ultrasonic time on the qualities of the precursors and the phosphors as well as the photoluminescent/ mechanoluminescent properties of the phosphors was analyzed by laser particle size analysis, specific surface area measurement, X-ray diffraction, scanning electron microscopy, plasma emission spectroscopy, and spectrophotometry, respectively. The results show that the ultrasound in co-precipitation process can improve the crystallinity of crystalline, and increase the actual doping amount of Eu2+/Dy3+ ions in the phosphors. Compared to the phosphor synthesized in the absence of ultrasound, the photoluminescent intensity and mechanoluminescent intensity excited by impacting on the sample of phosphor synthesized in the presence of ultrasound for 40 min can be increased by 45.67% and 148.73%, respectively. This is possibly due to the improved crystallinity and the increased actual doping amount of Eu2+/Dy3+ ions in the phosphor. Furthermore, the mechnoluminescent mechanism of Sr0.95Al2O4:0.02Eu2+, 0.03Dy3+ phosphor synthesized with respect to the effect of ultrasonic assistance was also discussed.