A high-performance liquid chromatography-quadrupole time-of-flight mass spectrometric(HPLC-Q-TOF MS) method was established for the identification on constituents in Armeniacae Amarum Semen and Persicae Semen.Meanwhile,the chemical constitutions difference between Armeniacae Amarum Semen and Persicae Semen were analyzed by chemical pattern recognition methods-The sample was firstly extracted with methanol,then separated on an Agilent SB-C18 column(150 mm×3.0 mm,2.7 μm) by gradient elution,with 0.1% formic acid water-acetonitrile as the mobile phase,and finally analyzed by MS in positive and negative modes-The qualitative analysis of chemical compositions was proceeded by online database,Agilent TCM PCDL database and fragmentation regularities of mass spectra,which were compared with those of standard samples.A total of 29 constituents were identified,including 8 glycoside compounds,6 amine acids,9 organic acids and 6 other compounds,in which glycoside compounds such as amygdaloside,prunasin,mandelic acid amide-β-gentiobioside,benzyl-β-gentiobioside,etc.were the main non-volatility constituents in Armeniacae Amarum Semen and Persicae Semen-Propyl-β-gentiobioside was firstly reported in these two traditional Chinese medicines.The mass data were pretreated with Profinder software.Combined with SIMCA-P software,a statistical model for the discrimination of constituents difference between these two medicines was established by unsupervised principal component analysis(PCA) and supervised orthogonal partial-least squares discriminant analysis(OPLS-DA) multivariate pattern recognition techniques-A clear distinction between Armeniacae Amarum Semen and Persicae Semen was presented when PCA and OPLS-DA were used.15 compounds showed significant differences between these two medicinal materials,which were mainly composed of glycosides,amine acids and fatty acids.Importantly,the content of propyl-β-gentiobioside in Armeniacae Amarum Semen outclassed that in Persicae Semen,which may be used as the potential chemical marker to distinguish Armeniacae Amarum Semen and Persicae Semen.This research provided a good support for pharmacology research and quality control on Armeniacae Amarum Semen and Persicae Semen.