Abstract: Objective: To investigate the relationship between lymphatic microvessel density marked by monoclonal antibody D2-40 and Helicobacter pylori L-form (Hp-L) infection in gastric cancer.Methods: The expression of D2-40 and Hp-L in the tissue samples of 100 cases of gastric cancer,50 cases of peritumoral tissues and 30 normal gastric tissues were detect by S-P immunohistochemistry;and Hp-L infection of the above tissues was calculated by Gram stain.Results: The LMVD was 12.61±4.20 per 100 visual field in the central area of the tumor;and the LMVD was 31.20±3.73 per 100 visual field in the peritumoral tissues,which was significantly higher than that in the central area of the tumor and the normal gastric tissues 9.23±5.62 per 100 visual field (P<0.01);the number of LMVD was significantly correlated with that of metastatic lymph nodes and Hp-L infection (P<0.01).Conclusions: The lymphatic microvessel density marked by monoclonal antibody D2-40 is correlated with Hp-L infection.