Objective To study the differences in physical characteristics of lacrosse balls and baseballs, so as to investigate the potential sports injuries caused by lacrosse balls. Methods Twelve lacrosse balls and 12 baseballs were used as testing samples. All testing balls were under conditioning control for 24 h to make sure temperature and humidity were consistent before measurement. The physical characteristics such as ball weight, circumference, compression-displacement and restitution coefficient were measured, respectively. Independent-sample t-test was used to compare the differences in lacrosse balls and baseballs. Results The lacrosse ball weighted (144.65±0.29) g, and its circumference, compression-displacement, and restitution coefficient were (19.97±0.02) cm, (91.76±1.23) kg and (0.633±0.011), respectively. The baseball weighted (146.12±0.45) g, and its circumference, compression-displacement and restitution coefficient were (23.20 ± 0.06) cm, (124.76±1.68) kg, and (0.528 ± 0.005), respectively. The lacrosse balls are significantly smaller in weight, circumference and compression-displacement than the baseballs (P<0.05). The restitution coefficient was significantly greater than baseballs (P<0.05). Conclusions The physical characteristics of lacrosse balls are in compliance with international standard. However, lacrosse balls have the same risk of causing serious injuries as baseballs. To reduce the risk of sports injuries, it is recommended that the specification of lacrosse balls need to be classified for different age and skill levels.