Objective To select the items related to the types and definitions of traditional Chinese medicine（TCM） constitution of preschool children using Delphi method

and to provide a basis for establishing a TCM constitution scale for preschool children. Methods Through the literature review

the standardization of items and the considerations of the practical application

the item pool of TCM constitution for preschool children was initially developed; and a questionnaire including TCM constitution types and the corresponding definition indicators was established. A three-round questionnaire survey was conducted in 17 experts from 11 provinces（municipalities directly under the Central Government） using Delphi method. The data on TCM constitution types and the corresponding definition indicators was calculated based on the positive coefficient of the surveyed experts

the concentration degree and the coordination degree of the opinions

and the final items were determined after the modification and deletion according to the experts′ opinions. Results Initially

there were 11 TCM consititution types and 209 items of constitution definition. The experts positive coefficient of the three-round questionnaire survey were 100%

100%

and 88.24%

respectively. According to the concentration and coordination degree of expert opinions

26 items were deleted and five items were added in the first round survey; seven items were deleted in the second round; and 27 items were deleted in the third round. Finally

nine TCM constitution types were remained including balanced constitution

qi deficiency constitution

yang deficiency constitution

yin deficiency constitution

phlegm dampness constitution

dampness heat constitution

qi constraint constitution

inherited special constitution

and yang heat constitution; and 154 items related to constitution definitions were determined

involving vigorous

refreshed

responsive

and well-nourished. Conclusion The nine TCM constitution types and 154 definition indicators of preschool children are initially constructed by the Delphi method

which can provide a basis for the further establishment of the TCM constitution scale for preschool children.