Fraxinus mandshurica is widely distributed around the world, which has significant economic value and pharmacological effects. However, its roots are often overlooked during processing and use. In this study, the preliminary identification of chemical components in F. mandshurica roots was carried out using ultra-performance liquid chromatography coupled with electrospray quadrupole time-of-flight mass spectrometry (UPLC-ESI-Q-TOF-MS), and a total of 37 characteristic components were identified, including 13 secoiridoids, 7 lignans, 6 coumarins, 4 flavonoids, 4 phenylethanols, 1 terpenoid and 2 other compounds. Meanwhile, to evaluate the 6 lignans content of F. mandshurica roots, the identification, quantitation analysis and methodological validation were performed by high-performance liquid chromatography with diode array detection mass spectrometry (HPLC-DAD-MS), which showed that the concentration range of standard compounds was 0.5–1000 μg/mL. The standard curve correlation coefficients (R2) were all greater than 0.9991, indicating that the linearity of the fitted curves was good. The highest lignan content in F. mandshurica roots was olivil (461.11 μg/g) and the lowest in buddlenol E (11.14 μg/g), and the total lignan content was 764.63 μg/g. The relative standard deviations (RSD, %) of both intra-day and inter-day precision were less than 1.95%. The RSD (%) of the reproducibility and stability experiments was less than 2.91%. The spiked recoveries of the samples were in the range of 98.29–102.62%, and the RSD (%) was in the range of 0.43–1.73, indicating that the method has high accuracy. In addition, a total of 20 volatile components in F. mandshurica roots were identified and quantified by gas chromatography-mass spectrometer (GC-MS) in this study, which laid a solid foundation for the comprehensive development and utilization of F. mandshurica resources.