The effects of quenching water temperature （20~60°C） on the structure， strength and toughness of 7B50 aluminum alloy plate were investigated by using room temperature tensile test， fracture toughness test and the combination of scanning electron microscopy and transmission electron microscopy （TEM）. Besides， the sensitivity of different aging treatment systems to the quenching water temperature was also studied. The results show the room temperature tensile properties of 7B50 alloy are not sensitive to the quenching water temperature. However， the fracture toughness tends to increase as the quenching water temperature decreases. When the quenching water temperature decreases from 60°C to 20°C， the fracture toughness of the peak-aged and over-aged alloys increase by 12.9% and 11.4%， respectively. The fracture toughness of the peak-aged alloy is more sensitive to the quench water temperature when the quench water temperature is higher （40 °C and 60 °C） compared with the over-aged alloy. TEM obseration results reveal the relationship of the fracture toughness change due to the grain boundary microstructure. As the quench water temperature decreases， the size of the grain boundary precipitation phase of the quenched alloy gradually decreases. Furthermore， the size of the grain boundary precipitates decreases and the width of the precipitates free zone of the aged alloy becomes narrower. Especially， the grain boundary precipitates size and the width of the grain boundary precipitates free zone of the peak-aged alloy varied more significantly with the temperature change.