I have hole in ear drum and nothing else so for that i had an tymnoplasty surgery.my current hearing is 60 db.how much it improve after this surgery?

Not sure: There are 2 main types of hearing loss: sensorineural (inner ear) and conductive (problem with sound getting to the inner ear). A hole in the eardrum may cause conductive loss, but you may also have a separate inner ear problem as well. Therefore, it is unclear how much hearing improvement would be expected with surgery. Ent and audiology evaluation would clarify this.

Depends: Usually a hearing test is done preoperatively to determine how much hearing loss exists and how much of the hearing loss is related to the perforation (hole). One can predict to some degree the amount of expected improvement based upon this and other factors. This is something you need to address with your surgeon.