Objective To summarize the important role of myeloid differentiation factor 88 （MyD88） in toll like receptor （TLR） signaling pathway， and to summarize the relationship between MyD88 and relative diseases， and its potential application value. Methods Domestic and international publications online involving the role of MyD88 in TLR signaling pathway and the influence of MyD88 in some kinds of diseases in recent years were collected and reviewed. Results MyD88 was an important adapter protein， and played a connecting role in the TLR signaling pathway. It was the bottle neck of TLR signaling pathway， and could lead to the activation of many transcription factor to initiate innate immune response. It was also related to a variety of diseases. Conclusions MyD88 is the key adapter protein in TLR signaling pathway. It plays an important role in innate immunity， acquired immunity， and a variety of diseases， so it is a potential therapeutic target.