Abstract: Bitter almonds (Semen Armeniacae Amarum) are prone to oil deterioration during storage, so they often require mashing prior to clinical use. To confirm the medical value of bitter almonds "being mashed when used" and to determine the optimal storage conditions for bitter almonds, UPLC-MS/MS was used to perform a comparative study of the chemical composition of bitter almonds in different storage states (mashed and unmashed), storage times (0, 2 and 4 weeks), and storage temperatures (25 ℃ and 4 ℃). A total of 58 substances were identified in bitter almond extracts through literature review, this group's previous work, and a Compound Discoverer software search. Statistically significant differences were found in the chemical composition and content of bitter almonds in different storage states, storage times, and storage temperatures. The results show that the chemical composition of bitter almonds stored unmashed was more stable than that of bitter almonds stored mashed; the chemical composition of bitter almonds stored at 4 ℃ was more stable than that of bitter almonds stored at 25 ℃; and the shorter the storage time, the less the chemical composition changed. Amygdalin, the main medicinal component of bitter almonds, showed statistically significant differences in content under the above three storage conditions, which can be used as a potential quality marker for bitter almonds.