Background High glucose (HG) induced podocytes injury plays an important role in diabetes nephropathy (DN) development. Long noncoding RNA cancer susceptibility candidate 2 (CASC2) was found to be decreased in serum of DN patients. We aimed to explore the function and possible mechanism of CASC2 in HG induced podocytes injury. Methods Under normal glucose (NG), HG and mannitol stimulated podocyte conditions, the levels of CASC2, microRNA-9-5p (miR-9-5p) and peroxisome proliferator-activated receptor gamma (PPARγ) were examined by quantitative real-time polymerase chain reaction (qRT-PCR). Podocyte injury was evaluated by measuring cell viability and apoptosis of CIHP-1 cells were checked by cell counting kit-8 (CCK-8) assay and flow cytometry, respectively. Western blot was used to detect all protein levels. Dual-luciferase reporter, RNA immunoprecipitation (RIP) and RNA pull-down assays were performed to confirm the relationship between CASC2 and miR-9-5p. Results HG stimulation inhibited the expression levels of CASC2 and PPARγ, but promoted the expression of miR-9-5p. HG could restrain cell viability, autophagy and facilitate apoptosis in CIHP-1 cells, while CASC2 overexpression could reverse HG-induced podocytes injury. Furthermore, CASC2 could be used as a ceRNA to adsorb miR-9-5p, and miR-9-5p mimic overturned the effects of CASC2 on cell viability, autophagy and apoptosis in HG-stimulated podocytes. Additionally, PPARγ was a target gene of miR-9-5p, and CASC2 could weaken the HG-induced podocytes injury by up-regulating PPARγ. Conclusion CASC2 increased cell viability, autophagy and inhibited cell apoptosis by regulating miR-9-5p/PPARγ axis, thus reducing the HG-induced podocytes injury.