Cannabidiol (CBD) is one of the most abundant cannabinoids in industrial hemp.Many animal and clinical studies have shown that CBD,as a new drug,has excellent antidepressant,psychiatric and immunomodulatory effects,almost without side effects.We focus on the domestic and abroad research progress in the synthesis,physiological function,separation and purification of CBD.It is pointed out that at present,most of the studies on CBD are focused on the therapeutic effect and anti-inflammatory effect of CBD on neurological diseases,and other functional activities need to be explored and developed.The existing separation and extraction procedures are complex,so it is urgent to find industrial production processes with high efficiency and low cost.Chemical synthesis has many advantages compared with direct extraction from plants,but the existence of analogues in the synthesis makes it more difficult to purify CBD,so the study of new synthesis methods is also an important part of CBD research.