The portable embedded-based automatic weather station fault detector has been developed to meet the demand for rapid diagnosis of automatic weather station faults. It integrates a low-power microcontroller, high-precision electronic components and high-speed data communication module in a unified way. It isolates the microcontroller data bus and the weather element processing circuit bus through a four-channel digital isolator to enhance the anti-interference between signals, and realizes the simulation and acquisition of wind direction, wind speed, rainfall, temperature and humidity, and barometric pressure signals to realize the fault detection of automatic weather stations. The test results enlighten that the instrument can quickly locate the fault point, which comes from the automatic weather station sensor, collector, power module, communication module, etc. The error of the output analog weather signal is not more than 0.3, and the average error of signal acquisition is stable around 0.2.