In this study, we revealed for the first time the function of RNU12 and its related molecules in GC: (1) RNU12 was downregulated in GC with negative relation to lymph node metastasis; (2) RNU12 could sponge miR-575 and upregulate BLID, then BLID functioned as a tumor suppressor; (3) RNU12 could control proliferation, colony formation, migratory, invasion through RNU12/miR-575/BLID axis; (4) RNU12 exerted the tumor-suppressing effect via regulating the expression regarding CCND 1, PCNA, N-cadherin, E-cadherin, Vimentin and anti-apoptosis BCL-2. This evidence concerns the gene PCNA and gastric cancer.