OBJECTIVE To study the absorbed components of Xiebai powder in blood. METHODS UPLC-Q-TOF-MS/MS method was adopted. SD rats were randomly divided into blank group and administration group ，with 10 rats in each group. Blank group was given water intragastrically ，and administration groups were given 2 g/mL（by the amount of crude drug ）Xiebai powder solution intragastrically. Administration volume was 11.3 mL/kg，twice a day for 3 days. One point five hours after last administration，blood was taken from the abdominal aorta of each rat ，the serum was processed to obtain the supernatant for analysis；the relevant data in positive and negative ion mode were collected ，and the absorbed components of Xiebai powder in blood were analyzed and identified by using self-built secondary mass spectrometry database and consulting the relevant literature. RESULTS Totally 17 components from Xiebai powder were identified ，among which 6 components came from sovereign Moru salba，7 from minister Cortex Lycii ，12 from assistant Glycyrrhiza uralensis ，i.e. kukoamine A ，chlorogenic acid ，tachiogroside B，astringin，neoglycyrrhizin，glycyrrhizin，azelaic acid ，isoglycyrrhizin，glycyroside，anthocyanin，sebacic acid ，parthenolide， anthocyanin，18β-glycyrrhetinic acid ，6-gingerol，palmitoamide，erucamide. These compounds were mainly flavonoids ，alkaloids and organic acids. CONCLUSIONS In this study ，17 absorbed components of Xiebai powder in blood are preliminarily determined，which are consistent with the effect of Xiebai powder. They may be the pharmacodynamic substances of Xiebai powder.