Background　Heat and moisture exchanging filter is a kind of artificial device used to replace the upper respiratory tract and the nose function， with a certain degree of heat preservation， moisture and filtration function.　Objective　To summarize the heat and moisture exchanging filters and their complications for clinicians to use the devices appropriately.　Content　Through summarizing a large number of clinical and laboratory research literature， we objectively described three major functions of the heat and moisture filter and its influencing factors， and also introduces in detail the possibility of complications.　Trend　With the deepening of the clinical and laboratory research， heat an moisture exchangeing filter will be further improved and perfected.