Objective To observe the distribution of serum thrombospondin-1. platelet total and platelet parameters in children with Kawasaki disease and children in the control group, to explore deeply the law of changes of platelets，and relation between TSP-1 and changes of platelets, its potential mechanisms. Methods Serum TSP-1 were measured by Enzyme-linked immunosorbent assay, PLT and platelet parameters were measured by Automatic Hematology Analyzer in 32 cases of KD inpatients of pediatric department during September 1 st, 2011 and December 31st, 2012, 30 cases of children in similar ages in the control group were measured the same indicators during the same period，relative data were analyzed. Results (1) Serum TSP-1 was highest in acute phase and decreased little by little; PLT reached the peak in sub-acute phase; The activity of platelet reached the strongest level in acute children with KD and decreased then. (2) There was no correlation between the level of serum TSP-1 and PLT in acute, sub-acute and convalescent phase. Conclusions (1) The level of serum TSP-1 is related to the activity of the platelet, it can be used as an indicator to evaluate the extent to which the activity of platelet reaches. The activity of platelet reaches the strongest in acute children with KD.（2）Inhibition to thrombocytosis is unclear in children with KD, it needs more deep investigation.