Objective：To assess the mechanism of the variation of serum uric acid in obese patients with different body mass index（BMI）. Methods：Retrospective analysis was performed in 269 obesity patients with BMI≥28 kg/m2 from the authors’ affiliated hospital. According to their BMI，they were respectively divided into three groups，including the mild，moderate and severe obesity groups. Serum uric acid，anthropometric and metabolic characteristics of patients were measured. Each group was compared and the correlation between serum uric acid level and other index was analyzed. Results：The serum uric acid levels in all the obesity patients were increased with the increasing BMI，and which in male obesity were higher than that in female obesity（P < 0.05）. The prevalence of hyperuricemia in these obese patients also increased with BMI，which in male and female severe obesity patients were both more than 70%. Serum uric acid in all obese patients was positively correlated with BMI，fasting insulin，HOMA-IR and IL-6. Conclusion：Serum uric acid levels and the prevalence of hyperuricemia were both increased with the increasing BMI. Hyperuricemia is positively correlated with BMI，insulin resistance and inflammatory factors.