Objective To study the ultrastructural features of lymphatic vessels in human gastric carcinoma and discuss the metastasis mechanism of malignant cells by lypmphatic vessels. Methods The central, peripheral and normal regions of gastric cancer were obtained from postoperative samples of patients. Common resin embedded specimens were made. Lymphatic vessels were localized by hemithin sections under light microscope and observed by ultrathin sections under transmission electron microscope.Results There was no lymph vessel in carcinomatous central region. Compared with the normal region, the peripheral region of gastric carcinoma was found with more lymphatic vessels(t=3.270,P=0.002),more destroyed lymphatic vessels (χ SUP>2/SUP>=15.674,P=0.000),more interendothelial openning junctions（χSUP>2/SUP>=12.895,P=0.000）,and smaller lumina (t=-5315，P=0.000). Compared with gastric carcinoma without lymph node metastasis, there were more lymphatic vessels in peripheral region of gastric carcinoma with lymph metastasis（t=2.523，P=0.021）, more destroyed lymphatic vessels（χSUP>2/SUP>=5.281，P=0.022), and there was no statistical significance in the numbers of interendothelial opening and nonopening junctions （χ SUP>2/S