Potassium aluminum sulfate ［KAl(SO4)2］,also known as alum,is often added to the production process of fans to improve the characteristics of poor tenacity and easy fracture of fans,and it can also improve the taste of vehicles to a certain extent. The aluminum element in aluminum potassium sulfate has neurotoxicity,reproductive toxicity,and developmental toxicity. Long-term excessive intake of aluminum will do great harm to human health. In the conventional determination of aluminum potassium sulfate in vermiculate,the sample must be digested,and the treatment method is tedious and time-consuming. The portable X-ray fluorescence spectrometer (XRF) has the advantages of small size,simple operation,fast detection speed,and high sensitivity,and it can also determine a variety of metal elements at the same time. Therefore,taking vermin as the research object and using Inductively coupled plasma mass spectrometry (ICP-MS) as the reference,this paper established a new method for XRF to quickly detect and identify KAl(SO4)2 in vermin. XRF technology was used for the first time to identify whether KAl(SO4)2 was added to fans. Firstly,the matrix effect of the instrument was corrected by the equation,and the linear curve of peak area and concentration was established. The R2 of the corrected working curve was >0.99,which could be used to determine vermicular samples. Secondly,the detection conditions of the instrument are optimized. When the samples were directly tested on the machine,the relative error of XRF test results was 0.65%～24.33%. For vernacular samples with aluminum content less than 100 mg·kg-1 in KAl(SO4)2,rapid carbonization treatment can be used to determine the low content of aluminum in vernacular samples after enrichment. The relative error of XRF test results is 1.36%～15.39%,and carbonization treatment greatly reduces the relative error of direct determination of samples. In addition,it was found that there was a correlation between Al,S,and K elements in the standard samples with aluminum potassium sulfate,and the ratio of the three elements was in the range of 1∶3∶1~1∶4∶1,while the ratio was not satisfied in the samples without aluminum potassium sulfate. Portable XRF can efficiently complete the bulk samples; single test process needs time for about 5 min; method is rapid,simple,and economical,with high precision and can quickly identify the fans whether adding KAl(SO4)2,food quality,and safety hidden danger in time,to the quality of the fan control provides a new way of thinking,has extensive practical popularization significance.