JiaMing,
It may help other to know exactly what it is that you want: a specific photo, a specific type of helicopter, or are you seeking generic helicopter photos for general use?
If it is the latter then I would suggest that you follow the links given here, if you can. If not then it would help to be a bit more forthcoming since no-one is likely to provide you with their copyrighted material without knowing for what purpose you intend to use it.