Circular RNA (circRNA) sirtuin-1 (SIRT1) is differentially expressed in non-small cell lung cancer (NSCLC), but its specific mechanism is still uncertain. The study was to figure out the latent molecular mechanism of circSIRT1 in NSCLC. The results clarified that circSIRT1 and SMAD family member 7 (SMAD7) were downregulated, but microRNA (miR)-510-5p was upregulated in NSCLC. CircSIRT1 expression was linked with tumor-node-metastasis staging and tumor size in NSCLC patients. Elevating circSIRT1 or suppressing miR-510-5p refrained NSCLC cell activities and glycolysis and inactivated the wnt/β-catenin pathway, while knockdown of circSIRT1 promoted the malignant behavior of NSCLC cells. Besides, inhibition of malignant behavior in NSCLC cells by elevating circSIRT1 was reversed by knockdown of SMDA7. circSIRT1 bound to miR-510-5p to target SMAD7. In short, circSIRT1 represses NSCLC cell malignant development via miR-510-5p to target SMAD7, making it a latent target for NSCLC treatment.