The ultrathin MoS2-coated carbon nanospheres have been prepared by a facile solvothermal method using acid-treated carbon nanospheres (ATCNS) as support. TEM images show that ATCNS are homogeneously coated by MoS2 layers. The thickness of MoS2 coating on ATCNS is about 5 nm. XRD data confirm that the few stacking layers and low crystalline of MoS2 nanosheets on ATCNS, which could provide more active sites for hydrogen evolution reaction (HER). The electrocatalytic activity and stability of MoS2/ATCNS for HER have been investigated. The results show that MoS2/ATCNS has better electrocatalytic activity for HER than pure MoS2. It can be speculated that ATCNS play crucial role in increasing conductivity and electrocatalytic activity for HER of MoS2/ATCNS. The nanostructure of ultrathin MoS2 coating on ATCNS is a promising electrocatalyts for HER.