Objective To study the development of infant-toddler social and emotional traits in Shanghai. Methods Brief Infant-Toddler Social and Emotional Assessment (BITSEA) scales were used in children aged 12~36 months in Shanghai.840 samples were enrolled and 100 samples were re-tested the reliability at the interval of 1 to 3 weeks.The two main factors (behavior problem,competence) and five sub-factors (Externalizing,Internalizing,Dysregulation,Autism Spectrum Disorder and Red Flag) were analyzed. Results 1) The Cronbach alpha coefficients were 0.55~0.81.The test-retest reliabilities were 0.79~0.87 (P<0.01).2) There were more behavior problems in small age groups.Competences in 12~17 months were lowest.The statistics had significant differences in age groups (F=4.84,15.30,P<0.01).Girls had better competences than boys (t=-2.53,P<0.05).3) The autism spectrum disorder had a negative correlation with competence.There were differences between groups in boys.4) The red flag problems could reflect certain behavior problems. Conclusion The early screening of children's social and emotional problems can predict certain behavior problems,which will be of valuable guidance.