High stromal ratio of gastric cancer is associated with a poor prognosis. Fibronectin 1(FN1) is the main component of gastric cancer stroma. The focus of this research was to investigate the FN1 express pattern, the connection between FN1 expression, clinicopathological parameters, survival, and mismatch repair genes (MMR) or immune checkpoints in gastric cancer patients. Eighty-six paired stomach cancer tissues, neighboring normal tissues, and eight independent gastric cancer tissues were used to create 180 points tissue microarrays. The association between epithelial fibronectin (E-FN1), stromal fibronectin (S-FN1) expression, and clinical characteristics was analyzed using the chi-square test or Fisher's exact test, and the survival analysis curve was analyzed using the log-rank test, followed by univariate and multivariate Cox regression. The correlation between FN1 and MMR or immune checkpoints was analyzed by Spearman correlation. FN1 is mainly expressed in gastric cancer tissues, with low or no expression in adjacent normal tissues. In tumor tissues, FN1 is mostly distributed in the stroma. High E-FN1 expression was associated with a decreased overall survival (OS), while S-FN1 expression did not. High S-FN1 expression correlated with older age (P < 0.001), higher pathological grade (P < 0.001), pathological type (P < 0.001), vessel/lymphatic invasion (P < 0.001), advanced T stage (P = 0.001), N stage (P = 0.01), and worse TNM stage(P = 0.033). FN1 expression was not associated with MMR or immune checkpoints (MLH1, MSH2, MSH6, PDL1, PD1, PMS2, and CD8). High E-FN1 expression predicted poor OS, while S-FN1 is associated with gastric cancer progression. [ABSTRACT FROM AUTHOR]