I have uploaded an app to app store and it is accepted by app review team also.
But i have kept the release in my hand and thats why app is showing "hold for developer release".
Now my question is that there any limit for time or developer can release even after a month or year?
Apple's iTunes Connect Guide says (page 116):
If you have an app in the Pending Developer Release state for longer than 30 days, you receive an email reminder from Apple.
It doesn't say (anywhere I could find) that there's any particular time limit, but the above quote leads me to believe that under 30 days is probably fine, over 30 days maybe not.