AIM: To investigate the clinical value of miniature ultrasonic probes (MUPs) for the diagnosis and treatment of digestive tract diseases.METHODS: Endoscopic ultrasonography (EUS) was performed for patients with its indications with 7.5-20 MHz MUPs and double-cavity electronic endoscope. According to the diagnosis of MUPs, patients who had indications of treatment received endoscopic resection or surgical excision.Postoperative histological results were compared with the preoperative diagnosis of MUPs. A few patients without endoscopic resection or surgical excision were periodically followed up with MUPs.RESULTS: A total of 537 patients were examined by MUPs, of them, 256 were diagnosed with gastrointestinal submucosal lesions, 146 with pseudo-submucosal lesions,50 with digestive tract cancers, 17 with peptic ulcer, 11with cholecystolithiasis, 8 with chronic pancreatitis, and 2with achalasia and 47 were diagnosed as normal. After MUPs examinations, 220 patients received endoscopic resection or surgical excision, and the postoperative histological results of 211 patients were completely consistent with the preoperative diagnosis of MUPs. The diagnostic accuracy of MUPs was 95.9%. The result of follow-up with MUPs indicated that gastrointestinal leiomyoma, lipoma,phlebangioma and cyst were unchanged within 1-2 years.The patients who received endoscopic resection or centesis did not have any complications.CONCLUSION: MUPs are of value in diagnosing gastrointestinal submucosal lesions, staging of digestive tract cancers and biliary-pancreatic diseases. They play a very important role in making therapeutic plans.