The development of single photon detector is an important research topic in the field of quantum optics and quantum information. Single photon detector broke through the limitations of traditional detector that only sample for amplitude,and simultaneously detect the polarization,wave vector and phase of light waves or photons,with advantages of maintaining measurement signal integrity,high theoretical quantum efficiency,low operating voltage,high detection sensitivity and the potential for room temperature single photon detection. In order to further understand the research status and development prospects of single photon detector,the working mechanism of the single photon detector is introduced. Then,the advantages and shortcomings of the traditional single photon detector such as photomultiplier tube and avalanche photodiode,as well as new single photon detector based on new two dimensional materials avalanche photodiode and superconducting nanowire single photon detector are summarized and compared,and the prospect of its development is prospected. In addition,the applications of single photon detector in areas such as quantum communication,laser ranging and imaging are introduced.