Objective To investigate the risk factors of the superior mesenteric vein (No.14v) lymph node metastasis in gastric cancer patients and their impact on prognosis. Methods The clinical data of 214 gastric cancer patients who underwent radical gastrectomy and No.14v lymph node dissection in our department from Apr. 2014 to Aug. 2018 were retrospectively analyzed. The patients were divided into 2 groups (No. 14v lymph node negative and positive groups) according to the postoperative pathological results, and pathological characteristics of the 2 groups were compared. The risk factors of No. 14v lymph node metastasis were analyzed by multivariate logistic regression. The relationship between No. 14v lymph node metastasis and the prognosis of patients with TNM stage Ⅲ or Ⅳ gastric cancer was analyzed by Cox proportional hazard regression model. Results No. 14v lymph node metastasis occurred in 34 (15.9%) patients. Univariate analysis showed that No. 14v lymph node metastasis was correlated with the age, depth of tumor invasion, lymph node metastasis, distal metastasis, TNM stage, differentiation level, tumor maximum diameter, neuroinvasion and vessel invasion (all P<0.05). Multivariate logistic regression analysis showed that TNM stage (odds ratio[OR]=2.749, 95% confidence interval[CI] 1.947-3.882, P<0.01), age (OR=2.773, 95% CI 1.140-6.745, P=0.025), and No. 3 (OR= 5.430, 95% CI 1.643-17.949, P<0.01) and No. 6 (OR=10.244, 95% CI 2.830-37.081, P<0.01) lymph node metastases were independent risk factors for No. 14v lymph node metastasis. Multivariate Cox proportional hazard regression analysis showed that No. 14v lymph node metastasis was an independent risk factor for the prognosis of patients with TNM stage Ⅲ or Ⅳ gastric cancer with age ≤65 years (hazard ratio[HR]=4.065, 95% CI 1.469-11.249, P=0.007). Conclusion For advanced gastric cancer patients with late TNM stage (especially late N stage) or with No. 3 and No. 6 lymph node metastases, No.14v lymph node dissection is recommended during operation.