Abstract: The asbestos including chrysotile,crocidolite and amosite in brake rubber of bicycle were determined by the X-ray diffraction method using base standard absorb correction. The preliminary break of sample,selection of filter films,and speed of rotating plate were studied. The quantity determination of low content (0.1%～1%) asbestos had been realized for the lowest quantification limit of these three asbestos were 0.054%,0.045% and 0.057% respectively.