The meso/bathypelagic organisms in the ocean serve as a crucial link between the epipelagic and bathypelagic food webs, playing an indispensable role in upholding the stability of the structure and function of the ocean ecosystem. Research on microplastic pollution in the meso/bathypelagic zone is limited due to the challenges associated with sample collection. Longnose lancetfish Alepisaurus ferox possesses a unique digestive mechanism and serves as an effective biological accumulator. This study quantitatively analyzed the abundance and physicochemical characteristics of microplastics in meso/bathypelagic species preserved within the stomachs of longnose lancetfish using laser infrared imaging spectroscopy. A total of 146 microplastics were found in the intestines of 7 species of meso/bathypelagic fish and cephalopods, with a detection rate of 85.71%. The average abundance was （10.43±12.12） items/individual, while the size ranged from 20.34 to 309.89 μm with an average size of （47.36±43.41） μm. The majority of microplastics were granules （59.58%） or fragments （36.30%）, with acrylic copolymer being the predominant polymer composition at 60.27%. This study demonstrates the feasibility of using longnose lancetfish as a biological sampler to investigate microplastic pollution in the meso/bathypelagic organisms for the first time. The results of this study are highly significant for analyzing microplastic pollution and its potential ecological risks in ocean ecosystems.