Objective To study the cut-off value of screening congenital hypothyroidism (CH),and to analyze the different clinical features prognosis and influencing factors of permanent congenital hypothyroidism (PCH),and transient congenital hypothyroidism (TCH). Method A total of 2 789 cases of CH were enrolled in this research.Clinical data of newborn CH,diagnosed and followed-up in the neonatal screening center from August 1999 to April 2013,were collected retrospectively.The incidence,screening TSH values and complications of CH were assessed.According to whether the cases stop L-Thyroxine at 2 or 3 years old,participants were assigned into two groups:PCH group (n=682) and TCH group (n=621).The clinical features,prognosis,prognosis relevant factors were studied comparatively to PCH and TCH.And the clinical features of preterm CH and low-birth-weight newborn CH were also described. Result The neonatal screening incidence of CH was 1/1 886 in this study,the screening TSH level≥10 mU/L accounted for 97.5% cases.The 682 cases of PCH and 621 cases of TCH were diagnosed.The radio of male/female,mean screening TSH value and inital dosage of PCH group were higher than those of TCH group (4.44∶1 vs 1.14∶1 and 96.4±82.3 mU/L vs 46.8±46.0 mU/L,respectively,P<0.01).While the infant's age of serum FT4 values recovered,and the normal percentage of stature,bone age,DQ or IQ assessment of PCH group were lower than those of TCH group [(57.8±16.4) d vs (68.2±75.7) d,87.9% vs 99.0%,92.9% vs 96.7% and 95.1% vs 98.4%,respectively,P<0.01].117 (PCH 22.2%) cases of preterm CH and 111 cases (PCH34.2%) of low-birth weight newborn CH were found.56 cases (8.2%) in PCH group reused L-Thyroxine during followed-up.The complicated incidence in 2 789 cases of CH was 2.1%. Conclusion The recommended cut-off value in screening CH is >9 mU/L.The outcome of TCH was better than that of PCH.The high level of TSH level implies PCH.Preterm CH and low-birth-weight newborn CH need to be treatedstandard.CH cases need long-term following-up and systemic examination.