In order to solve the problem of mutual interference between the feed circuit and the slewing circuit of the crawler drilling rig,the schematic diagram of LUDV hydraulic system was established to improve the energysaving effect and the reliability of the whole machine.Taking 1 000 N·m crawler drill as an example,the relevant technical parameters were calculated.A physical simulation model was built by using AMESim software.The flow saturation condition and undersaturation condition of LUDV hydraulic system were simulated respectively.The influence of the spring stiffness and system pressure difference of LS unit valves on the hydraulic system was obtained through analyzing dynamic characteristics of this system.The results can provide a theoretical basis for the application of LUDV hydraulic system in crawler drilling rig.