Objective To study the effects of partial hepatectomy (PH) on the ultrastructure of colon mucosa in rats. Methods Thirty-five healthy SD rats were divided into one normal control group, three sham-operation (SO) control groups and three operation (2/3 PH) groups. The rats in the SO and PH groups were sacrificed at the 6th, 12th and 24th hour after speration). The colon was collected and prepared as ultrathin sections. Samples were observed by transmission electron microscope (TEM). Results Compared with that in the normal control group rats, the ultrastructure of colon mucosa did not show distinct changes in the SO groups. However, significant changes were observed in PH 6- and 12- hour groups rats, for example, the microvilli became short, enterocyte interspace was greatly increased, mitochondria of goblet cells was impaired, endocrine cells were stimulated, degranulation of mast cells was marked, macrophages were filled with phagosomes, neutrophilic granulocytes were gathered to lamina propria. In PH 24-hour groups, endocrine cells were still active, but other changes were not evident. Conclusion After PH, colon mucosa barrier is acutely damaged which leads a rising rate of infection. However, stimulation of endocrine cells and mast cells may be helpful to liver regeneration and recovery.