Screening and mining efficient polyethylene terephthalate (PET)-degrading enzyme is a promising strategy for plastic waste treatment and recycling. This invention provides a novel transcription factor-based biosensor method for identifying potential PET-degrading enzymes from the microorganisms. When PET is degraded by a specific enzyme to produce terephthalic acid (TPA), the transcription factor TphR recognizes the TPA substrate and then activates the transcription of downstream green fluorescent protein (GFP) reporter, generating measurable fluorescence signals in bacterial cells.