The simultaneous determination of trace elements in ultrafine agaric was carried out by inductively coupled plasma atomic emission spectrometry (ICP-AES). The experiments were done using wet acid digestion sample preparation. The samples were dissolved at 120 ℃ constant temperature. The requirements of determination by ICP-AES can be satisfied at an acidity controlled less than 10%. The method is simple, rapid and economic. National standard material GBW07602 was detected by authentication. Its accuracy is between 1.12% and 6.15. The precision is between 0.41% and 5.69%. At thesame time, the surface structure of ultrafine agaric powder was examined by scanning electron microscope. And the dietary fiber was determined for fungus protein, crude fat, crude fiber, moisture and ash content by chemical analysis. The study on external and internal relevance of agaric could provide a new approach to scientific research on the development and application of fungus dietary fiber.