Gastric cancer is one of the most common lethal malignancies in the world, especially in China. Due to the ineffective screening of early gastric cancer and drug resistance of the advanced, the prognosis of gastric cancer remains dismal. Based on bioinformatics and tissue microarray analyses, FBXO5 was selected for analysis in this study. Here, we report the function of FBXO5 in gastric cancer, showing for the first time that it contributes to tumor cell proliferation, clone formation, invasion and migration. In these preliminary findings, FBXO5 promoted the transition of the cell cycle from the G0/G1 to the G2/M phase, which likely resulted from FBXO5 interacting with CDK1 and NCAPG proteins. The relevant mechanism needs to be explored. In addition, FBXO5 participated in the tumor microenvironment and was negatively related to immune activation. FBXO5, an oncogene, plays a role in tumor initiation and progression, and is expected to be a potential target for gastric cancer treatment.