Background:Because of the controversy in clinical nutritional support therapy of hydrolyzed protein formula milk and standard preterm infant formula (SPIF) in premature infants. In this study, the effectiveness and safety of preventive use of hydrolyzed protein formula milk in reducing gastrointestinal diseases and promoting physical development of premature infants are scientifically evaluated by systematic evaluation. To help find the suitable nutritional support for premature infants.Methods:To search the database of Chinese and English by computer: SinoMed, CNKI, WanFang Data, VIP, PubMed, EMbase and The Cochrane Library, and to collect randomized controlled trials on the application of hydrolyzed protein formula milk in nutritional support treatment of premature infants compared with SPIF. The retrieval time limit is from the establishment of each database to September 1, 2020. Two authors independently completed the paper search, and sorting out the main outcome indicator and secondary outcome indicator in the selected literature, and the data are statistically analyzed by Review Manager software (RevManV.5.3.0) and STATA 13.0.Results:This study will provide a high-quality evidence on the effects of hydrolyzed protein formula milk on gastrointestinal diseases and physical development of premature infants.Conclusion:At present, the clinicians are controversial about the safety and effectiveness of hydrolyzed protein formula milk and SPIF in the nutritional support therapy of premature infants. This study will compare the effectiveness and safety of these 2 nutritional support methods, and make a comprehensive analysis of the influence of hydrolyzed protein formula milk on gastrointestinal diseases and physical development of premature infants, and finally give a positive conclusion.OSF registration number:DOI 10.17605/OSF.IO/UQD92