Objective To develop the Todller Attachment Quetionnaire and build its attachment discriminant function. Methods The privary attachment questionnarie was derived from the items pools based on the 90 items of Attachment Q-set(AQS)and had been revised by an discussion with 6 experts of child development.The parents of 612 toddlers aged 1～2 years come from 8 cities fulfilled the todller attachment quetionnaire.With 6 exploratory factor analysis, the attachment questionnarie with 36 items built up through delete some in-effective items, and its reliability and validity were tested successively.With the data of strange situation procedure(SSP) testing and attachment questionnaries from 128 toddlers and their mothers, the attachment discriminant function was built finally. Results The attachment questionnarie consisted of 36 items, with 8 factors.Cronbach's alpha coefficient was 0.77, Guttman split-half reliability was 0.74, test-retest reliability was 0.56.Content validity and construct validity all were satisfied.The A type, B type and C type all had highly corrective discriminant results.There was no statistical significance between SSP types and AQS discriminant types (χ²=0.13, P=0.94). Conclusions The attachment questionnarie and its discriminant function are accord with psychometric demands, which can be used as a practicable instrument for people to evaluate toddler's attachment characters.