In order to improve the micro-motion,stability,response speed and positioning accuracy of crane slewing motion,digital hydraulic technology was applied to the slewing system of the crane.Based on digital hydraulic technology,a digital hydraulic slewing system of crane was designed.The structure and working principle of the digital hydraulic slewing system were introduced.The mathematical model of the digital hydraulic slewing system was established.A digital hydraulic slewing system was installed on a certain type of crane and compared with the original hydraulic slewing system.The experiment results show that compared with the original hydraulic slewing system of the crane,the minimum stable speed of the digital hydraulic slewing system is lower and more stable,and the micro-motion is better.The digital hydraulic slewing system is more stable when starting at high speed,and the maximum stable speed is higher.The response time of the digital hydraulic slewing system is greatly reduced,and the system response is faster.The digital hydraulic slewing system has the function of precise position control,and the repeated positioning accuracy is high.