Abstract: High-performance liquid chromatography(HPLC) with atmospheric pressure chemical ionization tandem mass spectrometry(APCI-MS) was used to analyze the main components and contents of bufadienolides in ChanSu crud durg and the baking processed product. The results indicated that there is not a new component generated but only decreased in holistic content of bufadienolides. HPLC-APCI-MSⁿ can quickly identify the components in ChanSu and its processed products.