Molybdenum disulfide (MoS2) nanosheets, a typical two-dimensional material,have received much attention for its unique tunable electronic structure and excellent electrocatalytic activity for hydrogen evolution reaction (HER). In order to further improve its electrocatalytic performance,in-depth investigations on microscopic HER mechanism have been conducted to elucidate the key factors influencing the electrocatalytic performance within the material's electronic structure and construct reasonable electronic descriptors. This paper reviews the origin,development and current status of the d-band center theory to probe the mechanism of MoS2 electrocatalytic HER in recent years,with a view to providing guidance for the further development of this type of catalyst.