OBJECTIVE: Vitamin D deficiency (VDD) is common among infants, especially in preterm babies. There are some controversies over its use on body development, immune function and incidence of bronchopulmonary dysplasia (BPD). METHODS: We systematically reviewed PubMed, Embase, and Cochrane databases for studies in English, and in Wanfang, VIP, and Cnki databases for Chinese studies (databases were last launched on 1 August 2016). RESULTS: Twelve original random controlled studies (seven in English and five in Chinese) were included (1). There are no differences between high-dose (800-1000 IU/d) and low-dose (400 IU/d) groups on calcium, phosphorus, and 25(OH)D concentrations (p > .05). However, length gain and head circumference gain are significantly increased in the high-dose group (p < .05) (2). IL-2, Ig-A, and Ig-G levels are significant increased in the vitamin D supplementation group compared with the control group (p < .05) (3). With respect to BPD, there is no significant difference between the vitamin D supplementation group and the control group (p > .05). CONCLUSIONS: In preterm infants, daily supplementation of vitamin D in doses of 800-1000 IU compared with 400 IU appears to be better not only in development but also in immune function. But clinical trials with a larger sample size are still needed.