Abstract: Objective?To seek good markers to predict invasion and metastasis of gastric adenocarcinoma (GAC). Methods?Expression of Kangai 1 (KAI1), CD34, and D2-40 were examined by immunohistochemistry containing 145 specimens of GAC and 50 specimens of normal gastric tissue. Microvessel density (MVD) and lymph vessel density (LVD) were determined by the mean number of small CD34-positive or D2-40-positive vessels counted. And the relationship of KAI1, MVD and LVD, as well as the role of them on invasion, metastasis and prognosis in GAC were analyzed. Results?The positive rate of KAI1, the median scores of MVD and LVD in normal gastric tissue and GAC tissue were 92.0%, (9.2±7.8)/LP, (7.5±7.6)/LP and 37.2%, (21.6±9.1)/LP, (22.6±12.7)/LP, respectively. And there was a significant different between the two groups (P<0.05). The expression of KAI1, the scores of MVD and LVD were significantly related with pathologic-tumor-node-metastasis (pTNM) stages, depth of invation and lymph node metastasis (all P<0.05). There was a significant relationship between the expression of KAI1 and the scores of MVD or LVD. The survival rate of the KAI1 -positive or KAI1-negative group was significantly different (P<0.01); the survival rates were significantly lower in MVD≥22's group than that in MVD<22's group, so was the same relationship between the LVD≥23's group and the LVD <23's group (both P<0.01). Cox regression analysis: pTNM stage, expression of KAI1, and the scores of MVD were independent factors of postoperative survival time in GAC (P<0.05). Conclusion?The combined detection of KAI1, CD34, and D2-40 has an important role in predicting the progression and prognosis of GAC.