Perilymphatic fistula（PLF） is defined as an abnormal communication between the fluid（perilymph） -filled space of the inner ear and the air-filled space of the middle ear and mastoid, or cranial spaces. At present the diagnostic criteria for perilymphatic fistula is the fistula hole confirmed by the microscope and endoscope between the middle ear and inner ear, the hole is located in the round or oval window, fractured bony labyrinth, microfissures, anomalous footplate, and can occur after head trauma or barotrauma, chronic inflammation, or in otic capsule dehiscence. Recently, the cochlin-tomoprotein（CTP） detected from the middle ear. CTP, the shortest isoform of cochlin encoded by the COCH gene, has been proven to be a perilymph-specific protein which is not expressed in blood, cerebrospinal fluid and saliva but is highly expressed in lymphatic fluid of the inner ear and is used as a diagnostic biochemical marker for perilymph fistula. The CTP test based on ELISA was performed on the lavage fluid of patients with suspected perilymph fistula to obtain comparatively accurate test results. This paper reviewed the diagnostic value of CTP in perilymphatic fistula.