This review article provides an overview of the current state of research on aged microplastics and their detection technologies in environmental matrices. It focuses on the aging process, qualitative identification, quantitative characterization, and chemometrics. The aging of microplastics involves photo-radiation, thermal radiation, biodegradation, and mechanical fragmentation, leading to changes in surface morphology, biofilm formation, chemical oxidation, thermal alternation, and mechanical deterioration. Qualitative identification methods include mechanical, thermal, and spectral techniques, while quantitative characterization is achieved through microscopy and mass spectrometry. Infrared and Raman spectroscopy are rapid and sensitive for chemical identification in complex environmental samples, and combining these techniques enhances detection accuracy. The review also highlights the advantages and limitations of each detection technique and their potential for investigating aged microplastics. Additionally, it discusses the challenges of identifying aged microplastics in open environments due to the modified properties and the presence of natural organic matter and pollutants. The article serves as a valuable resource for researchers working in the field of microplastics, providing insights into the current state of research and available detection techniques.This review article provides an overview of the current state of research on aged microplastics and their detection technologies in environmental matrices. It focuses on the aging process, qualitative identification, quantitative characterization, and chemometrics. The aging of microplastics involves photo-radiation, thermal radiation, biodegradation, and mechanical fragmentation, leading to changes in surface morphology, biofilm formation, chemical oxidation, thermal alternation, and mechanical deterioration. Qualitative identification methods include mechanical, thermal, and spectral techniques, while quantitative characterization is achieved through microscopy and mass spectrometry. Infrared and Raman spectroscopy are rapid and sensitive for chemical identification in complex environmental samples, and combining these techniques enhances detection accuracy. The review also highlights the advantages and limitations of each detection technique and their potential for investigating aged microplastics. Additionally, it discusses the challenges of identifying aged microplastics in open environments due to the modified properties and the presence of natural organic matter and pollutants. The article serves as a valuable resource for researchers working in the field of microplastics, providing insights into the current state of research and available detection techniques.