Cutaneous squamous cell carcinoma is the second most common cutaneous malignancy.Although the gold standard for squamous cell carcinoma is histopathological examination,thological tissue collection can cause trauma to patients.Therefore,optical non-invasive diagnostic techniques have received more and more attention.This article reviews the research progress of non-invasive skin imaging techniques,such as dermoscopy,high-frequency ultrasound,reflectance confocal microscopy,and skin optical coherence tomography,in the diagnosis and treatment of cutaneous squamous cell carcinoma in recent years.