Currently, accumulating documents have paid great attention to the critical role of long non-coding RNAs. The long non-coding RNAs DLEU1 has been demonstrated to be dysregulated in many solid tumors and hematological malignancies. However, the detailed descriptions about its potential roles and molecular mechanism in gastric cancer (GC) are still blurry. As for our research, it was found out that DLEU1 was observably intensified in GC tissues and cell lines. And highly expressed DLEU1 was relevant to tumor size, advanced stage of pathology and lymph node metastasis in GC patients. Silenced DLEU1 obviously suppressed proliferation via leading to the cell cycle arrest and inducing cell apoptosis of GC. Furthermore, mechanistic experiments uncovered that DLEU1 could recruit LSD1 (lysine specific demethylase 1) to the promoter regions of KLF2 and then suppressed its transcription. In addition, rescue assays revealed that the oncogenic function mediated by DLEU1 in GC was partly by regulating KLF2. Collectively, our findings manifested that DLEU1 might serve as an oncogene in GC.