Abstract： Objective To investigate the incidence and the gene mutation frequencies and patterns of β-thalassemia (β-Thal) in ethnic Han children in Chongqing city.Method A total of 1726 children were screened by using automatic hemocytic analyzer,cellulose acetate electrophoresis and fetal hemoglobin alkali denaturation test.Samples with mean corpuscular volume (MCV) ＜ 80 fl,cell hemoglobin content (MCH) ＜ 27 pg and hemoglobin A2 (HbA2) levels ＞ 3.3％,fetal hemoglobin (HbF) ＞ 2％ for β-Thal screening indicators.The positive samples of screening indicators were detected and identified by PCR-reverse dot blot method for 18 common β-Thal mutations in Chinese populations,unknown mutations samples were subjected to DNA sequencing analysis of the β-globin gene.Result Twenty-five cases of β-Thal carriers were observed from the 1726 samples,with 24 cases of β-Thal heterozygote and one case of double heterozygote.Therefore,the β-Thal carrier rate was 1.51％.After 1726 peripheral venous blood samples analyzed by hematological parameters,164 positive cases of β-Thal screening indicators were found,with the positive rate being 9.50％ (164/1726).A total of 6 different gene mutations were detected,the four most common mutations were as the following:CD41-42,IVS-Ⅱ-654,CD17 and beta E.These four mutations as the major types in this area accounted for 88.00％ of all the mutations.In addition,one rare mutation of 5 ' UTR ; + (43-40) was found,and one case of the hemoglobin variant of Hb Zurich was reported in Chinese people for the first time.Conclusion Chongqing is a high risk region of the β-Thal.Epidemiological Data from the research was useul for the genetic counseling and the prevention of β-Thal major.