Objective To systematically review the effect of adjustable fortification on feeding during preterm hospitalization. Methods We searched Cochrane Library, Web of Science, PubMed, China National Knowledge Infrastructure, Wanfang, Chongqing VIP for clinical controlled trials about adjustable fortification in premature infants. The retrieval time limit was from the establishment of each database to September 2022. We selected studies according to inclusion and exclusion criteria, extracted data and assessed their quality, then used RevMan5.3 for analysis. Results A total of 5 randomized controlled studies, 1 historical controlled study and 3 case-control studies were included, including 750 premature infants. Meta-analysis results showed that compared with the standard fortification group, the differences of body weight growth rate [mean difference (MD)=1.61 g/(kg·d), 95% confidence interval (CI) (0.73, 2.49) g/(kg·d), P=0.0003], body length growth rate [MD=0.15 cm/week, 95%CI (0.01, 0.29) cm/week, P=0.04], head circumference growth rate [MD=0.19 cm/week, 95%CI (0.06, 0.31) cm/week, P=0.003], incidence rate of necrotizing enterocolitis [relative risk (RR)=0.23, 95%CI (0.07, 0.75), P=0.01] were statistically significant in the adjustable fortification group. There was no significant difference in the incidence of feeding intolerance between the two groups [RR=0.58, 95%CI (0.31, 1.11), P=0.10]. Conclusion Adjusted fortification has a positive role in promoting the physical development of premature infants without increasing the incidence of feeding intolerance and necrotizing enterocolitis. When the growth of premature infants is poor after using standard fortification, adjustable fortification can be considered. However, due to the lack of included literature, more large sample, high-quality randomized controlled studies are needed in the future to further verify the feeding effect of adjustable fortification on premature infants.