Small nucleolar RNA host gene 1 (SNHG1) has been identified to function as an oncogene in a large number of human cancers. Nevertheless, the biologic role and underlying molecular mechanism of SNHG1 on cisplatin (DDP)-resistance in NSCLC is still unknown. qRT-PCR assay was performed to assess the expression levels of SNHG1 and miR-140-5p. Western blot analysis was used to determine Wnt1, cyclinD1, c-Myc and β-catenin levels. The direct correlation between SNHG1 and miR-140-5p was verified by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. CCK-8 assay and Transwell assay were applied to determine cell proliferation ability, and cell migration and invasion capacities, respectively. Tumor xenograft was performed to confirm the effect of SNHG1 on DDP-resistance of NSCLC in vivo. Our data showed SNHG1 was upregulated in DDP-resistant NSCLC tissues and cell lines. SNHG1 knockdown suppressed the proliferation, migration, invasion and DDP-resistance in DDP-resistant NSCLC cell lines in vitro and inhibited tumor growth in vivo. Moreover, SNHG1 repressed miR-140-5p expression by directly binding to miR-140-5p. SNHG1-knockdown-mediated regulatory effect was antagonized by miR-140-5p. Furthermore, Wnt/β-catenin signaling was involved in SNHG1/miR-140-5p-mediated regulation in DDP-resistance of NSCLC cell lines. The results suggested that SNHG1 knockdown ameliorated DDP-resistance of NSCLC by regulating miR-140-5p/Wnt/β-catenin pathway, providing a new potential therapeutic target for DDP-resistance NSCLC treatment.