The invention discloses an ambroxol hydrochloride oral solution and a preparation method thereof, and relates to a preparation method of western medicine, in particular to a medical production formula used for curing bronchitis and a preparation method thereof; the preparation method comprises the following steps: sucrose, preservatives and purified water are dissolved in a mixing mode so as to prepare simple syrup; the ambroxol hydrochloride, corrigents and preservatives are dissolved by the purified water so as to prepare ambroxol hydrochloride solution; the ambroxol hydrochloride solution and the simple syrup are stirred and mixed evenly, the corrigents and the preservatives are added successively and discontinuously and then the purified water is added to adjust the concentration. The invention has simple and reasonable process, and is easy to operate practically and the produced products have good stability; the products can used as common phlegm-eliminating drugs, has functions of increasing the liquid level of the respiratory tract, reducing mucus secretion, enhancing the secretion of pulmonary surfactant and the movement of cilium and preventing cough to a certain extent, and is applicable to acute respiratory disease and chronic respiratory disease, such as ropy sputum and difficult cough caused by acute bronchitis and chronic bronchitis, bronchial asthma and pulmonary tuberculosis, etc.