Microplastic (MP) pollution has gradually become a significant environmental concern, as MPs are widely present in soil, beaches, oceans, and even the atmosphere. Rapid detection and identification of MPs are crucial for monitoring and assessing environmental pollution. In this study, a fusion and solvent evaporation ionization (FSEI) device, comprising a heated plate and nebulizer, was developed for the direct detection and identification of six types of MPs. In the mass spectra, these MPs presented characteristic mass intervals corresponding to the monomer, realizing a more intuitive identification. After optimization, FSEI-MS demonstrated high sensitivity, good linearity (