目的　观察 3周模拟失重对大鼠后肢骨形态、生物力学特性和生长情况的影响。　方法　 14只雄性 SD大鼠按体重配对后随机等分为对照组和模拟失重组 ,采用尾部悬吊方法模拟失重 ,3周实验结束后处死大鼠 ,取后肢骨检测股骨物理性状、生物力学特性、钙含量以及胫骨组织学变化 (三色染色法 )。　结果　 3周悬吊期间大鼠生长良好 ,未出现明显应激反应 ;与对照组相比 ,3周模拟失重组大鼠股骨湿重、干重、灰分、直径和密度均降低 (P<0 .0 1) ;弹性载荷、最大载荷、刚性系数等均下降(P<0 .0 1) ,最大挠度和韧性系数增大 (P<0 .0 1或 P<0 .0 5 ) ;钙在股骨头部位百分含量降低 (P<0 .0 5 ) ,在股骨干有下降的趋势。切片三色染色结果显示胫骨哈佛氏系统周围骨样组织钙化障碍 ,原有钙化基质内钙盐脱钙现象明显。　结论　 3周模拟失重使大鼠后肢骨生长受抑 ,钙盐代谢障碍 ,生物力学性能降低 Objective To observe the effects of three weeks simulated weightlessness on the morphology, biomechanical properties and growth of rat hindlimbs. Methods Fourteen male Sprague-Dawley rats were randomly divided into control group and simulated weightless group according to their body weight. The tail suspension method was used to simulate the weightlessness. After 3 weeks, the rats were sacrificed and the physical properties and biomechanical properties , Calcium content and tibial histological changes (trichrome staining). Results Compared with the control group, the rats’ weight, dry weight, ash, diameter and density of femur in 3-week simulated weightlessness group decreased significantly (P <0. (P <0.01), the maximum deflection and the toughness coefficient increased (P <0.01 or P <0.05); calcium in the stock The percentage of bones decreased (P <0.05), there was a downward trend in the femoral shaft. Tricolor stained sections showed calcification of bone-like tissue around the Harvard tibia system, the original calcification matrix calcium decalcification phenomenon. Conclusion Three weeks’ simulated weightlessness inhibits the growth of rat hindlimb bone, reduces the metabolism of calcium and reduces the biomechanical properties