Abstract: The contents of cadmium and arsenic in dried Auricularia auricula were rapidly detected by high definition X-ray fluorescence (HDXRF) spectrometry. In the process of the experiment, the dried Auricularia auricula samples were pre-treated, and the three experimental conditions of particle size, sample weight, and instrument measurement time were optimized. Figures of merit such as precision, reproducibility, and stability were evaluated. The results showed that, the optimal detection conditions of HDXRF were: particle size of 100 meshes, sample weight of 0.80 g, and measurement time of 600 s. This method allowed direct detection of cadmium and arsenic in 15 min, and a detection limit of 0.035 mg/kg of cadmium and 0.012 mg/kg of arsenic, respectively. The relative standard deviations (RSD) of precision, reproducibility and stability of HDXRF were all below 10%. Finally, the results of HDXRF were compared with inductively coupled plasma mass spectrometry (ICP-MS). The results were accurate and the relative errors were less than 20%. It indicates that the method of HDXRF can meet the rapid detection requirements of cadmium and arsenic in dried Auricularia auricula.