Objective:To establish a method for the determination of Si migration in penehyclidine hydrochloride injection packed with low borosilicate glass ampoule. Methods: Si migration was determined by graphite furnace-atomic absorption spectrometry. Re-sults:The linear concentration range was 0-85 ng·ml-1(r=0. 995 6). The average recovery was 95. 85% and RSD was 4. 60% (n=9). Conclusion:The method is sensitive, rapid and accurate with good repeatability, which can be used to determine Si migration in penehyclidine hydrochloride injection packed with low borosilicate glass ampoule.