The invention provides a method for preparing ambroxol theophylline-7-acetate and belongs to the field of chemical medicine. The method takes water, ethanol or methanol as a solvent, the theophylline-7-acetic acid and ambroxol alkali react with the weight ratio of 1 to 1.49 to 1.69, and the ambroxol theophylline-7-acetate is prepared, and the ratio of the theophylline-7-acetate and the solvent byweight ratio is 1 to 20 to 60. The steps of the method are simple, the content of the obtained ambroxol theophylline-7-acetate is more than 98 percent, and the weight yield rate is more than 113.0 percent calculated in ambroxol alkali. As taking water as the reaction solvent, the method has the advantages of low cost, easy recovery and treatment and reducing the pollution of organic solvent emission to the environment.