Gastric cancer is the main leading cause of cancer-related death worldwide. The aberrant expression of paternally expressed gene 10 (PEG10) is involved in development of a range of cancers. However, the potential biological function and the underling mechanism of PEG10 in human gastric carcinoma are still unknown. Knocking down LncRNA PEG10 might represent a promising therapeutic strategy for the treatment of gastric cancer. The expression of PEG10, miR-3200, and AEG1 in human gastric carcinoma NCI-N87 cells were altered by cell transfection assay. Cell viability, migration, invasion, and apoptosis were determined by trypan blue exclusion, Transwell assay, and flow cytometric analysis, respectively. RNA and protein expression level of gene was analyzed by real-time PCR and Western blot. Luciferase reporter assay was conducted to determine the target gene of miR-3200. JNK and Wnt signal pathway protein expressions were tested by Western blot. The up-regulation of PEG10 was found in clinical samples. PEG10 knockdown effectively inhibited gastric carcinoma cell viability, migration, and invasion, but promoted cell apoptosis. This tumor-suppressing effect of PEG10 knockdown might be realized by up-regulating miR-3200 in vitro and in vivo. AEG1 was a direct target gene of miR-3200. Moreover, miR-3200 might suppress NCI-N87 cells by negative regulating AEG1. Up-regulating miR-3200 effectively blocked JNK and Wnt pathways likely via down-regulating AEG1. PEG10 knockdown played a carcinostatic role via up-regulating miR-3200 and further regulating AEG1 in gastric carcinoma cells, during which process, JNK pathway and Wnt pathway were blocked.