Objective: Exploring the prognostic value of butyrylcholinesterase (BCHE) in gastric cancer (GC) and analyzing its impact on the biological functions of gastric cancer cells. Research methods: Firstly, Lasso regression method was used to screen prognostic genes, and the relationship between BCHE expression levels and clinical pathological parameters was verified using chi-square test. In addition, TIMER 2.0 database and CIBERSORT algorithm were utilized to investigate the correlation between BCHE and immune cell infiltration, and enrichment analysis was performed using WGCNA algorithm and DAVID Bioinformatics Resources database. Finally, the expression levels of BCHE in normal gastric epithelial cell line (GES-1) and gastric cancer cell lines (HGC27 and MKN1) were detected by real?time qPCR. Following transient transfection of small interfering RNA was conducted to knockdown the expression of BCHE in HGC27 and MKN1 cell lines. Cell proliferation was detected by CCK-8 and colony formation assay. Cell adhesion ability was detected by adhesion assay. Cell migration and invasion were detected by transwell and scratch assay. Results: Fifteen genes related to the prognosis of GC patients were screened using LASSO regression analysis. Among them, BCHE has the best predictive value. Further analysis indicated that the expression level of BCHE in GC tissues were higher than that in the adjacent tissues or healthy controls, while the expression of BCHE in tumor cells was closely related to immune cell infiltration related molecules. Enrichment analysis showed that the high expression of BCHE was related to cell proliferation, migration and adhesion. The results of in vitro experiments further confirmed that reducing the expression of BCHE significantly inhibited the malignant biological function of gastric cancer cell line. Conclusions: BCHE serve as a prognostic biomarker for GC and can promote immune cell infiltration in tumors. In addition, reducing the expression of BCHE can inhibit its mediated malignant biological function.