Terahertz wave has unique advantages, such as being transient, broadband, penetration and low energy, which shows a very broad application prospect in the research of materials science, information communication, environmental monitoring, national defense, medical services etc. As the key of the application in this field, terahertz detector has attracted much attention. Graphene has two advantages for detector. Firstly, the linear band structure makes it possible to absorb terahertz photon and convert to current or voltage. Secondly, it has ultra high carrier mobility so that it could realize ultrafast detection. Therefore, graphene is expected to be the suitable material for new generation of high performance detectors in the terahertz band. The development of terahertz detectors based on graphene in recent years is summarized in detail.