Acne scars on face deep can fractional laser improve how much percent ?

It can improve 71%: In one study the patient satisfaction was 71%.

Many options: There are a variety of methods to improve acne scars - the best method(s) depend upon the nature of the scars. Fractional co2 lasers are very helpful. Some scars may be so deep that surgical excision of the scar is the best solution. There is no way to obtain 100% improvement but more than 50% improvement with a single treatment should be expected.

Partially: Honestly, deep acne scars are difficult to treat with our current methods. At best, even with a good laser resurfacing treatment, 50% improvement would be considered a "good result".