In order to enhance the stability of vitamin D2 (VD2), the inclusion complex of VD2 with beta-cyclodextrin (beta-CD) was added in" Longmu Zhuanggu Chongji", a medicine of children for the prevention and cure of rickets. The VD2 in beta-CD-VD2 inclusion complex was satisfactorily determined by both reversed-phase high performance liquid chromatography (HPLC) and ultraviolet spectrometry (UV). The experimental results from UV were in well consistent with those from HPLC. The accuracy and recovery of HPLC measurement were analyzed, and their relative standard deviation (RSD) were given to be 0.63% and 1.54%, indicating the method is quite correct and reliable, and the linear regression equation is reasonable. The" Longmu Zhuanggu Chongji" containing beta-CD-VD2 inclusion complexes was saponified by a mixture of KOH, vitamin C (VC) and alcohol-water (1: 2, V/V) at 70 degrees C, then extracted with petroleum ether. An accurate content of the VD2 product was obtained by HPLC. A simple and rapid HPLC method, which can detect VD2 in the inclusion complex and in" Longmu Zhuanggu Chongji", has been established in this work.