Modern pharmacological studies revealed that Celastrol exhibits anti-inflammation, anti-bacteria, anti-virus, anti-fertility, insect-resistance functions and has been used for the treatment of rheumatism, rheumatoid arthritis, blood diseases, skin diseases and agricultural insecticide. The present study aimed to investigate the effects of Celastrol on glucocorticoid-induced osteoporosis (GIOP) and the underlying molecular mechanisms. The findings of the current study revealed that Celastrol reduced body weight, urine calcium/creatinine, tartrate-resistant acid phosphatase 5b, C-terminal telopeptide of type I collagen, and induced osteocalcin in GIOP rats. In addition, alkaline phosphatase, triiodothyronine receptor auxiliary protein and cathepsin K mRNA expression levels were effectively suppressed, and osteocalcin, bone morphogenetic protein 2, type I collagen and runt-related transcription factor 2 mRNA expression levels were effectively induced in osteoporosis rats treated with Celastrol. Celastrol inhibited prostaglandin E2 and caspase-3 protein expression levels, and induced phosphoinositol 3-kinase (PI3K), phosphorylated-protein kinase B (AKT) and glycogen synthase kinase-3 phosphorylation, Wnt and beta-catenin protein expression in GIOP rats. The present study demonstrated that Celastrol may inhibit GIOP in rats via the PI3K/AKT and Wnt signaling pathways.