I wanted to change the file permission when I use "git", but the "chmod" didn't work. How can I use "chmod" command under the NTFS file system?
You can't. See: https://askubuntu.com/questions/11840/how-to-chmod-on-an-ntfs-or-fat32-partition
The mode is determined by the partition's mount options (you cannot change it via chmod).
For '755' on files and '777' on directories you would use something like
sudo mount -t ntfs -o rw,auto,user,fmask=0022,dmask=0000 /dev/whatever /mnt/whatever