With increasingly severe network security threats and increasingly complex security defense means， zero trust network is a new evaluation and review of traditional boundary security architecture. Zero trust emphasizes never always trusting anything and verifying things continuously. Zero trust network emphasizes that the identity is not identified by location， all access controls strictly execute minimum permissions， and all access processes are tracked in real time and evaluated dynamically. Firstly， the basic definition of zero trust network was given， the main problems of traditional perimeter security were pointed out， and the zero trust network model was described. Secondly， the key technologies of zero trust network， such as Software Defined Perimeter （SDP）， identity and access management， micro segmentation and Automated Configuration Management System （ACMS）， were analyzed. Finally， zero trust network was summarized and its future development was prospected.