Objective: To investigate the levels of serum vitamin D and IgE in infants with different allergic risks and to analyze their correlations. Methods: In the present study, the participants were selected and recruited from the infant ward of our hospital from February 2012 to December 2012. A total of 120 patients were selected and recruited. Among these patients, 64 patients with symptoms of allergic diseases were assigned to the experimental group. The remaining 56 patients who had respiratory infections, but without other symptoms of allergic diseases, were assigned to the control group. The serum 25-hydroxyvitamin D3 levels were measured using liquid chromatography tandem mass spectrometry and the IgE levels were measured using radioimmunoassay in both experimental and control groups. Subsequently, the serum 25-hydroxyvitamin D3 levels and IgE levels were compared between the experimental group and control group. Results: The following findings were obtained through data comparison. The serum 25-hydroxyvitamin D3 level in the experimental group was 18.19 ± 7.84 ng/mL, and the IgE level was 551.51 ± 705.88 IU/mL. The serum 25-hydroxyvitamin D3 level in the control group was 21.95 ± 7.834 ng/mL, IgE level was 49.39 ± 32.46 IU/mL. The data comparison indicates that the serum 25-hydroxyvitamin D3 level in the control group was higher than the experimental group, and the IgE level in the control group was lower than the experimental group (P<0.05). Conclusion: The level of vitamin D3 in patients with allergic symptoms is relatively low. This may be one of the causes leading to allergies. At the same time, IgE is also one of the causes contributing to allergies. An elevation of the IgE level is very likely to cause the allergic, and there is a correlation between serum vitamin D and IgE levels. At the same time, research has found that proper supplementation of vitamin D3 can help prevent allergic diseases, and can be considered in a new and high-quality program for the prevention of allergic diseases.