In order to improve the efficiency of crane operation, ensure operational safety, and improve the intelligent level of crane operation, a crane motion state monitoring method based on digital twin is proposed. Firstly, according to the operating characteristics and real-time monitoring requirements of the existing experimental prototype-spider crane, a digital twin framework for telescopic cranes is proposed, and the functions of each part are elaborated in detail; secondly, a virtual model of crane digital twin is constructed, data acquisition, classification, transmission and parsing are carried out, and kinematics analysis of the crane is carried out to realize real-time state mapping of cranes, and it is verified that the crane digital twin motion state monitoring system can provide fine motion state monitoring, which provides a new idea for intelligent crane operation.