The utility model provides an apparatus for removing hydraulic system impurity, which comprises an oil tank; a hydraulic main loop for sucking oil from an oil suction port and returning oil to the oil tank by an oil returning port, wherein, the hydraulic main loop comprises a hydraulic pump, a filter, a field device which are arranged in series, the filter is positioned between the hydraulic pump and the field device, the filter comprises a signal transmitting device and a filter core which are connected in parallel. A pressure pipeline filter is added in a main pipeline of the hydraulic system, accordingly, the impurity in the hydraulic system can be eliminated in time, thereby avoiding the impurity entering into the pipeline and then into a hydraulic cylinder and a hydraulic valve.