Calcipotriol is a derivative of vitamin D, which combines with VD3 receptor on the cell surface and regulates the synthesis of DNA and keratin in cells. It can inhibit the excessive proliferation and induce the differentiation of skin cells (keratinocytes), so as to correct the abnormal proliferation and differentiation of psoriasis skin cells. At the same time, it can regulate the release of inflammatory factors, inhibit inflammatory infiltration and proliferation, and play an anti-inflammatory role. It has better therapeutic effect on psoriasis of scalp and other special parts.