In order to know the influence of passive smoking to children's health, the smok ing state of children's family members and health condition of 1031 children who were 4-6 years old and in 4 kindergartens which condition and source of childre n were similar were investigated with questionnaire made by ourselves. The child ren were divided into groups upon their quantity of passive smoking, the height and weight of 949 children were measured and the suphocyanate in saliva of 485 c hildren selected among 1031 children were examined. The results indicated:①the proportion of children suffered from respiratory system diseases≥4 times and co ld≥4 times in a year were increased upon the increasing of quantity of passive smoking, the quantity of passive smoking were positive related with times of suf fering from respiratory system diseases in a year; ②the quantity of passive smo king were positive related with concentration of sulphocyanate in saliva;③ the height and weight were decreased with the increasing of quantity of passive smok ing, the quantity of passive smoking was negative correlative to height and weig ht, especially for the younger. Passive smoking can influence the children's gro wth.