I have a Maxtor 4G120J6 120G can mount F: but cannot read directory.

I tried as below
1. MHDD SCAN 2 times & have some UNC & AMNF errors. It can mount in Windows F: but I cannot read the directory. And Windows prompt the format hard disk request.
2. MHDD MAKEBAD. I let it finished around 300M & I stop it.
3. I connect it to Windows but it cannot mount the driver letter anymore.

Does it mean all data lost?
If not, what can I do?

Why you made 2 x Scans? If you identify surface errors in the first scan performing additional scans can never be good.

Also, why you make command 'MAKEBAD'? My guess is this case is beyond any repair and needs to be cloned with a decent imager and data recovered from the image.

If you have no access to decent imager, or have no experience in this then consult a pro.

yes i don't have experience on handling it. would you mind tell me how to restore the data?

Yes.

Ship it to a professional who can SAFELY restore your data without the risk of permanent data loss.