没有英文缩写，儿童节快乐用英语表达就是Happy Children's Day!

类似的短语还有

新年快乐：Happy New Year Day!

生日快乐：Happy Birthday!

教师节快乐：Happy Teachers ' Day！

端午节快乐：Happy dragon Boat festival！

国庆节快乐：Happy National Day!

中秋节快乐：Happy Middle-autumn Day！