Based on embeded technology a portable fault detection equipment for the construction machinery hydraulic system is developed. The equipment is mainly composed of embeded hardware platform and graphical-interface software platform. The hardware platform includes the core control unit ECM-945GSE industrial computer, 8-channel data acquisition module based on ARM chip, LCD screen, touch screen, power supply module with large-scale operation voltage and wide temperature range, PTT pressure transducers, the integration transducer of temperature, pressure, flow rate transducer as well as equipment chassis. The software system consists of data acquisition procedures, diagnosis, detection and output printing programs and drivers programs. The pilot trial in the armed forces shows that both detectors can be used in repair shop or indoor, but also in the field of construction machinery on-site emergency repair when rapid detection and diagnosis. And it has a strong adaptability.