To study zinc deficiency on pathological changes of femur epiphyseal growth plate in rats thirty Wistar rats were randomly divided into three groups: zinc-deficient group (Zd), control group (Ctr), and pair-fed group (Zp) to study the effects of zinc deficiency on femur epiphyseal growth plate of rats and the mechanism involved. After 8 weeks feeding, the histomorphology of right femur indicated that chondrocytes in the epiphyseal growth plate of Zd group were generally ill-organized and mis-shaped. The number of chondrocytes decreased. Trabecular bone in the epiphyseal of Zd group were also ill-organized, scarce and slim. The cavities of marrow in Zd animals were significantly larger than those of Ctr and Zp. The volume of trabecular bone, the mean trabecular plate density of Zd rats were significantly decreased, but their mean trabecular plate space was significantly increased. In addition, the Zd animals had significantly lower concentration of osteocalcin and growth hormone in sera. The above results suggested that zinc deficiency impaired proliferation and differentiation of chondrocytes and balance between osteoblast and osteoclast function by reduce growth hormone levels in sera. The lack of zinc in diet resulted in disorder of bone molding and ultrastructure.