Abstract: Objective To analyze the occurrence of small for gestational age infants (SGA) in Zhuang ethnicity region and the effects of pre-pregnant body mass index (BMI), gestational weight gain and pregnant anemia on SGA, to provide rationale to develop better health care for pregnant women. Methods A total of 2 199 pregnant women of single pregnancy were selected as the participants, who received the first prenatal examination during the first 6 to 13 weeks of gestation in Pingguo People's Hospital, Child Health Hospital and Long'an People's Hospital from January to December 2016, data of the general conditions of pregnant women, regular prenatal examination records, the pregnancy outcomes etc were collected. t-test, χ² test and Logistic regression model were used for statistical analysis. Results A total of 327 infants were SGA, and the incidence of SGA was 14.87%. After adjusting the confounding factors, compared to the normal pre-pregnant BMI group, the pre-pregnant BMI <18.5 kg/m² group showed increased risk of SGA (OR=2.09, 95% CI:1.59-2.75, P<0.001), compared to the normal gestational weight gain group, women with insufficient gestational weight gain had increased risk of SGA (OR=2.19, 95% CI:1.67-2.86, P<0.001) among their infants. There was no significant difference in the risk of pregnant anemia on SGA (all P> 0.05). Conclusion Pre-pregnant BMI<18.5 kg/m², insufficient gestational weight gain are risk factors for SGA in Zhuang ethnicity region.