Objective To investigate the protective effect of withaferin A (WA) against high fat diet induced obesity and its associated mechanism.   Methods C57BL/6 J mice at 8-week of age were divided into two groups. The mice were fed with high fat diet (HFD) and were given an intraperitoneal injection of WA or DMSO (solvent control). The body weight and food intake of the mice were monitored. One week later, inguinal white adipose tissue (iWAT), interscapular brown adipose tissue (BAT), epididymal white adipose tissue (eWAT) and retroperitoneal white adipose tissue (rWAT) were collected and weighed. Expression levels of the genes associated with white adipose browning were detected in iWAT. HE staining was applied to observe the morphological changes of iWAT.   Results The data showed that body weight and fat weight in WA group were significantly lower than those in the control group, and the food intake was not changed significantly. Real-time PCR analysis showed that the expression level of browning related genes in iWAT of the WA group was significantly increased. The result  from Western blotting analysis showed that the protein levels of uncoupling protein 1(UCP1) and peroxisome proliferator-activated receptor gamma coactivator 1 alpha(PGC1α) increased significantly in iWAT of the WA group. The typical morphological change of adipose browning, such as the multilocular adipocytes was observed in inguinal white adipose tissue of the  mice treated with WA by using HE staining and mmunofluorescence assay.  Conclusion Taken together, these observations indicate that withaferin A can protect the mice from high fat diet induced obesity by promoting white adipose tissue browning.