Abstract: The ultraviolet spectrophotometric method and colorimetric method are used for thedetermination of isoprenaline hydrochlorid aerosol. The former is carried out bymeasuring absorbance at 279nm±mm. The absorption coefficient of isoprenaline isdetermined,E_(1cm)~(1%)279nm=112.8; The latter method is based on the reaction ofisoprenaline with sodium nitrite-sodium molybdate at alkaline medium forming a redcompound. By measuring the absorption of such red compound at 500±mm, it ispossible to determine the isoprenaline content in the sample. The concentration rangeof isoprenaline is between 4～40μg/ml, which is in agreement with Beer's laws.Theisoprenaline in the aerosol is also determined colorimetrically. Interferences to owning guaiphenesin and ascorbic acid are negligible.