Objective To investigate the factors influencing 25-hydroxyvitamin D

3

[25-（OH）D

3

] levels in the serum of children with infectious diarrhea. Methods Eighty cases of children with infectious diarrhea admitted to a hospital in Nanyang from February 2019 to February 2021 were selected as the observation group

and 40 healthy child volunteers recruited from the hospital during the same period were selected as the control group. The serum 25-（OH）D

3

levels of children in the 2 groups were compared

and the risk factors affecting serum 25-（OH）D

3

levels were analyzed. Results Forty children with infectious diarrhea with normal serum 25-（OH）D3 levels and 40 children with infectious diarrhea with deficient serum 25-（OH）D

3

levels were included in this study. The serum 25-（OH）D

3

level of children in the observation group was 31.26±5.33 μg/L

which was lower than that of the control group（38.01±6.54 μg/L）

and the difference was statistically significant（t=6.054

P

<

0.001）. The results of multifactorial logistic regression analysis showed that not taking vitamin D preparations or taking them indiscriminately

breastfeeding alone

low maternal literacy

recurrent upper respiratory tract infections

recurrent diarrheal disease

and recurrent bronchial asthma were risk factors affecting serum 25-（OH）D

3

levels in children with infectious diarrhea. Conclusion 25-（OH）D

3

deficiency is one of the important causes of the development of infectious diarrhea in children

and there are many risk factors affecting serum 25-（OH）D

3

levels in children with infectious diarrhea; active interventions on risk factors can significantly improve the condition of children.