To investigate the effect of minocycline on expression of iNOS and apoptosis after spinal cord injury(SCI)in rats. Adult SD rats were divided at random into two groups:with pressure to cause spinal cord injury and use minocycline group(group A),and use normal saline group(group B).After operation the rats were sacrificed at 4 h,8 h,1 d,3 d,7 d,14 d and 21 d after surgery,and then the tissue sections were stained with hematoxylin and eosin(HE),immunohistochemistry and terminal deoxynucl-eotidyl transferase-mediated dUTP nick end labeling(TUNEL)method,and the injured spinal cord tissue was evaluated. The histopathology changes in spinal cord tissue observed with HE staining microscopic examination in group B was worse than that in group A.Expression of iNOS and apoptotic cells were observed in two groups,and the apoptotic index and expression of iNOS in group B was higher than that in group A(P <0.05). This study demonstrated that minocycline can inhibit expression of iNOS and apoptosis after SCI in rats.