I have one ntfs partition in my pc, when i am trying to mount the ntfs drive it is showing the Error: unkown filesystem ntfs
where as i am able to mount the fat file system.
Thanks in advance.

You don't actually ask a question here, so I have to assume that you WANT to mount an NTFS partition, and can't. You also don't say anything about the version/distro of Linux you're using, or what you've tried, that gave you the error.

Type in "man mount", and it will give you the options for the mount command. Google can also help you, if you look. The option you want to look at is the "-t", which will specify the file system type. FAT support is very common, NTFS is getting there.

Try "mount -t ntfs-3g <device name> <mount point>"

I used this command
mount -t ntfs-3g /dev/hdb1 /mnt/Cdrive

But still the error persists.
unknown file system ntfs-3g.
man mount is not showing any file system types, which we can mount

Do you have ntfs-3g installed?

If not, go to http://www.ntfs-3g.org/ and follow their installation instructions.