Gastrointestinal endoscopy is a vital method for screening and diagnosing gastric cancer. It aids in identifying the tumor's location within the stomach and its macroscopic type, and allows biopsy for histological confirmation. Moreover, suspicious lesions can be further examined using specialized endoscopic techniques such as magnifying endoscopy (ME) combined with electronic staining, chromoendoscopy, confocal laser endomicroscopy (CLE) and fluorescence endoscopy. ME combined with electronic staining has been confirmed to achieve excellent diagnostic accuracy in distinguishing between noncancerous and cancerous lesions. However, ME is technically challenging, and gastric magnifying endoscopy involves various evaluation criteria such as the vessel plus surface classification system and Kudo's pit pattern classification, leading to a steep learning curve. Confocal Laser Endomicroscopy (CLE) is an advanced in vivo imaging technique that combines confocal microscopy with endoscopy, enabling real-time, microscopic visualization of tissues at a cellular level during endoscopic procedures. Despite having been available for approximately 20 years, and its accuracy in diagnosing gastric neoplastic lesions having been confirmed by several studies, the clinical application of CLE is not widespread, and there is a lack of relevant standards to guide the training of CLE endoscopists. To train more CLE endoscopists, we organized CLE training courses. We also evaluated the training's effectiveness and try to explore the Influencing factors of learning curve.