Abstract: The new psychoactive substances (NPSs) are defined as a category of substances of abuse, either in a pure form or a preparation, that are not listed in the control table by the 1961 Single Convention on Narcotic Drugs or the 1971 Convention on Psychotropic Substances, but may pose a public health threat. In July 2024, a total of 1245 individual NPSs have been reported to the United Nations Office on Drugs and Crime (UNODC) by 142 countries and territories worldwide. The growth in the number of NPSs has become a great challenge and a potential threat to global public health. The phencyclidine-type substances are classified into the group of dissociative NPSs, because they produce feelings of detachment and dissociation from self and the environment. These effects are produced through antagonism of ionotropic N-methyl-D-aspartate (NMDA) receptors in the central nervous system. Some of phencyclidine-type substances are scheduled as narcotics under the Administration of Non-Pharmaceutical Narcotic Drugs and Psychotropic Substances in China, including ketamine, 2-(2-fluoromophenyl)-2-(methylamino) cyclohexan-1-one (2-FDCK), 2-(ethylamino)-2-Phenylcyclohexan-1-one (2-oxo-PCE), 2-(2-bromophenyl)-2-(methylamino) cyclohexan-1-one (2-BDCK), 2-(ethylamino)-2-(2-fluorophenyl) cyclohexan-1-one (2-FXE), 2-(methylamino)-2-(2-methylphenyl) cyclohexan-1-one (2-MDCK) and so on. However, some new phencyclidine-type substances are produced by introducing slight modifications to the chemical structure of controlled substances to circumvent drug controls. These emerging substances have posed a significant challenge to the identification of forensic science laboratory around the world. Therefore, the knowledge of MS fragmentation pathways of known structure NPSs is very important for the structure elucidation of emerging new type of NPSs. In this study, a method based on gas chromatography-mass spectrometry (GC-MS) and liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF MS) was established for the analysis of phencyclidine-type NPSs in e-cigarette oil. The e-cigarette oil was extracted by methanol, then analyzed by GC-MS and LC-QTOF MS. The mass spectra were obtained under electron impact (EI) and electrospray ionization (ESI) modes, respectively, the structure and fragmentation pathways of main fragment ions were deduced. Finally, an unknown component was identified as a NPS of phencyclidine-type, 2-(propylamino)-2-phenylcyclohexan-1-one (2-oxo-PCPr), through structural analysis. Its characteristic fragment ion information acquired by GC-MS and LC-QTOF MS was similar to 2-oxo-PCE. This study provides a reference approach for the identification of small amount of NPSs by comprehensive analysis of their electron ionization mass spectrometry (EI-MS) and electron ionization tandem mass spectrometry (ESI-MS/MS) fragmentation patterns in the absence of reference materials.