This study showed that YAP1 was a downstream target of METTL3. The methylation level of YAP1 mRNA was reduced in gastric cancer cells inhibited by METTL14. These data further proved that the role of METTL3 in the development of gastric cancer was dependent on the methylation and activation of YAP1 and YAP1 signaling pathways, further confirming that m6A methyltransferase METTL3 promoted the proliferation and metastasis of gastric cancer by modifying YAP1 mRNA m6A. This evidence concerns the gene YAP1 and gastric cancer.