Objective：To investigate the effect of Weiweiqing in Chinese medicine for strengthening spleen，clearing heat and activating blood on ultrastructure of gastric mucosa in chronic atrophic gastritis(CAG)rats by observing the ultrastructural changes of gastric mucosal glandular epithelial cells and parietal cells in rats with CAG thus to preliminarily reveal the mechanism of Weiweiqing on CAG.Methods：Divided CAG rats into 6 groups randomly：the controlgroup，the modelgroup，the high-dose Weiweiqing group，the medium-dose Weiweiqing group，the low-dose Weiweiqing group and the folic acid group.Established a CAG ratmodelby app lying N-methyl-N'-nitro-N'-nitrosoguanidine(MNNG)and method of irregular diet.And observe the changes of ultrastructure of gastric mucosa in rats.Results：Compared with the control group，the main cells of the gastric mucosa of rats in the model group showed nuclear pyknosis，a large number of vacuolar degeneration in the cytop lasm，chromatin condensation in parietal cells and a reduced number of mitochondrial cristae.Compared with the modelgroup，the nucleolus structure of gastric mucosalmain cells in the high-dose Weiweiqing group and the medium-dose Weiweiqing group were still the same， and the rough endop lasmic reticulumwere basically neat， and the number of mitochondrial cristae in the parietal cells was increased.Compared with the model group，the pattern of nuclear nucleus of gastric mucosalmain cells in rats in the low-dose Weiweiqing group was more regular.The nucleus morphology of parietal cells changed and the number ofmitochondria decreased.The nuclear chromatin of the gastric mucosalmain cells in the folic acid group was more normal，and there was vacuolar degeneration in the cytop lasmand chromatin condensation in the parietal cells.The number of mitochondrial cristae was larger than that in the model group.Conclusion：Weiweiqing can improve the ultrastructures of gastric mucosal glandular epithelial main cells and parietal cells to a certain extent.It is speculated that one of the mechanisms to improve the ultrastructure of gastric mucosa is that Weiweiqing can improve the discomfort of patients with CAG may be.