Optical coherence tomography (OCT) is an optical diagnostic technique that provides non-contact, non-invasive tomographic imaging of microscopic structures of living ocular tissues.However, it requires the patient to be seated during the examination, which limits its use in infants and recumbent patients.Intraoperative OCT (iOCT) can be used in patients in the decubitus position to provide the surgeon with critical real-time information on anatomy and subtle lesions, improving the success and safety of the procedure.At present, the clinically applied iOCT types include handheld OCT, microscope-mounted OCT, microscope-integrated OCT and so on, among which integrated microscope-integrated OCT is the most widely used.iOCT is mainly used in a variety of fundus surgeries, retinal detachment reduction and proliferative diabetic retinopathy resection in retinal disease surgeries, and macular hole repair and anterior macular membrane stripping in macular surgery.During surgery, the use of iOCT can play a role in reducing surgical complications, detecting subclinical lesions, helping the surgeon make the most appropriate surgical decision, and predicting patient prognosis.This article reviewed the classifications of iOCT, as well as its advantages and disadvantages in the application of retinal detachment, diabetic retinopathy, macular epiretinal membrane, macular hole and other diseases to provide a reference for clinical practitioners.