objective: to discuss the influence of extracurricular exercise on high school girls’ bone density and bone metabolism. Method: choose 60 healthy high school students as the research objects, then divide them into exercise group and control group. Employ the Japan MODULAR automatic biochemical analyzer and Enzyme-labeled meter (S200) made in America Thermo Company to test the bone metabolism index; employ the lunar prodigy dual X-ray absorptiometry to measure bone density. Results: among the students of exercise group, their bone density of ward triangle, trochanter and lumbar L2 are higher than that of control group (P<0.01), mean density of hip femoral neck of these two groups has no statistically significant deference; the serum calcium, phosphorus concentration and BGP mean are higher than that of reference group((P<0.01), ALP is also higher than that of control group (P<0.05), tartrate resistant acid phosphatase mean is slightly lower than that of the reference group (P<0.01). Conclusion: long-term extracurricular exercise can effectively improve high school girls’ bone density and bone quality, and is conductive to improve their bone metabolism.