Abstract: Objective To study the effect of hemiepiphyseal compression on spinal growth by observing the histology of thoracic vertebrae after staple fixation. Methods Nine premature female goats were randomly divided into experimental group (n=6) and control group (n=3). Thoracic vertebrae of T6-T11 in experimental group were fixed with unilateral multi-segment cross intervertebral space staple fxation and those in control group were exposed but not fxed. Intervertebral disc and growth plates were taken from T8-T9 4 months after operation and observed with H&E and Giemsa staining. Results No scoliosis occurred in control group with no signifcant difference found in the height of growth plate, morphology of mastocytes in growth plate and chondrocytes in end plate. Mild scoliosis occurred with a Cobb angle of 17.9 °±5.6 ° in experimental group 4 months after operation. The height of growth plate over and below the intervertebral disc was significantly shorter in the compression side than in the noncompression side (1.27±0.34 mm vs 2.05±0.19 mm, 0.77±0.31 mm vs 2.1±0.29 mm). The number of mastocytes was smaller in the compression side than in the non-compression side with no signifcant difference between experimental group and control group. The morphology of mastocytes in growth plate was abnormal and the mastocytes in growth plate were irregularly arranged while the mastocytes in growth plate were regularly arranged and their morphology was normal with rich cytoplasm and intact nuclei in the compressed side of experimental group. The number, volume and cytoplasm of chondrocytes were smaller, the chondrocytes were less compactly arranged in end plate and the nuclei of chondrocytes were fatter in the compression side than in the non-compression side of experimental group. Conclusion Unilateral fxation of thoracic verterbrae and hemiepiphyseal compression inhibit the growth of growth plate and development of chondrocytes, thus leading to imbalanced development of spine at both sides.