[Abstract] Objective：To explore the effects of premedication with pronase in miniature probe scanner(MPS). Methods：A total of 40 patients who accepted MPS in our hospital were divided into two groups: lidocaine group(19 cases) and combined group(21 cases). Lidocaine group had oral lidocaine hydrochloride mucilage 10 ml 10 min before the examination and combined group took the same dose of lidocaine hydrochloride mucilage10 min and 20000 unit pronase 20 min before MPS. The visibility scores of image in MPS and gastroscope , the operation time were observed . Results：Combined group had significantly higher visibility score and longer checking time in comparison with lidocaine group.(P<0.01) Conclusion： Premedication with pronase in MPS effectively improves image visibility and reduces the operation time.