Objective:To study the correlation of uridine diphosphate glucuronosyl transferase 1A1(UGT1A1) gene polymorphism and neonatal hyperbilirubinemia among Dai ethnic group in Yunnan province.Methods:From January 2020 to December 2022, Dai neonates with unexplained neonatal hyperbilirubinemia admitted to three hospitals in Yunnan Province were prospectively enrolled into the hyperbilirubinemia group. Neonates hospitalized during the same period without hyperbilirubinemia were selected as the control group. The serum total bilirubin levels were measured and UGT1A1 gene sequencing was performed in all neonates. The differences of genotype frequency and allele frequency of UGT1A1 gene in the two groups were analyzed. Logistic regression analysis was used to analyze the effects of each mutation on hyperbilirubinemia among Dai neonates.Results:A total of 92 neonates were in the hyperbilirubinemia group and 86 in the control group. No significant differences existed between the two groups on following items: gender, age at admission, gestational age (GA), birth weight (BW), feeding pattern, white blood cell count (WBC) and hemoglobin level ( P>0.05).Three mutation loci were detected in the hyperbilirubinemia group (c.211G>A, c.1091C>T and c.1456T>G), with frequencies 45.7%, 3.3% and 2.2%, respectively. Two mutation loci were detected in the control group (c.211G>A and c.1091C>T), with frequencies 17.4% and 1.2%. Correlation analysis showed that c.211G>A frequency (45.7%) and A allele frequency (23.9%) in the hyperbilirubinemia group were significantly higher than the control group ( P<0.05). No significant differences existed in the frequencies of c.1091C>T and c.1456T>G between the two groups ( P>0.05). Logistic regression analysis showed that c.211G>A was risk factor of unexplained neonatal hyperbilirubinemia in Dai neonates ( OR=3.976, 95% CI 1.991-7.941). Conclusions:The most common mutation of UGT1A1 gene in Chinese Dai neonates with unexplained neonatal hyperbilirubinemia in Yunnan Province is c.211G>A, which increases the risk of hyperbilirubinemia.