UBXD8 is a membrane protein that mediates endoplasmic reticulum-associated protein ubiquitination and degradation by interacting with p97/VCP. Recently, lipid droplet proteomic studies show the lipid droplet localization of UBXD8. Besides, UBXD8 is also involved in triglyceride metabolism. However, the molecular mechanism by which UBXD8 regulates triglyceride metabolism is still obscure. Here we knocked out UBXD8 in mouse C2C12 myoblasts by CRISPR/Cas9. We selected 2 UBXD8 knockout (KO) clone cell lines from 26 possible KO clones. UBXD8 KO did not change the lipid droplet proteins expression pattern. However, UBXD8 KO led to the accumulation of neutral lipid. Furthermore, our data show that UBXD8 KO could alleviate palmitate-induced insulin resistance and rescue palmitate-induced apoptosis which was characterized by PARP splicing. In addition, the phenotype of palmitate-induced insulin resistance and apoptosis was reappeared after overexpressing UBXD8 in UBXD8 KO cells. These data suggested that UBXD8 plays an important role in lipid metabolism and its abnormity related insulin signal and apoptosis.