Objective: To analyze and identify the chemical compositions of n-butyl alcohol fraction from Gentiana rhodantha 95% ethanol extract by using ultra-performance liquid chromatography with quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF-MS). Method: The separation was performed on Waters BEH C18(2.1 mm×50mm

1.7 μm) with 0.01% formic acid solution-0.01% acetonitrile formate as mobile phase for gradient elution. The column temperature was 30℃

the flow rate was 0.4 mL·min-1. ESI ion source was used in the mass spectrometry

and the data were collected in positive and negative ion modes for data analysis by referring to relevant literature of G. rhodantha and comparing with the control product information. Result: The 33 chemical compounds were identified from the plant

including 10 iridoids

6 phenolic acids

5 flavonoids

6 triterpenoids

1 benzoic acid carboxylate

1 pyranone and 4 other types. 24 compounds among them were detected from this species for the first time

namely ferulic acid

demethylbellidifolin

3S

5R

6R

9S-tetrahydrox-ymegas-tigmane

lbellidifolin

gentiobiose

chiratin

secoxyloganin

α-amyrin or β-amyrin

28-hydroxy-α-amyrin(28-hydroxy-β-amyrin or 24-hydroxy-lupeol)

norswertianolin

quercetin-3-O-β-glucoside

3-O-acetoxy-uvao

2'-(2

3-dihyd-roxybenzoyl)-gentiopicroside

gentianose

gmephiloside

isoorientin-4'-O-glucoside

rindoside

macophyllosides A

macophyllosides B and rhodanthenone respectively

secologanoside

gentiside F

gentiside G and anthocyanidin. Conclusion: UPLC-Q-TOF-MS technology can be used to identify the chemical compositions of G. rhodantha quickly and accurately

providing references for its quality evaluation and application development.