It's now possible for you to use your full name from your Google+ profile, so that you have the same name on YouTube as on all other Google products and services.
You’ll see this option when you upload or comment on YouTube. For partners, brands, and organizations, you won’t see this just yet. To get started, go to upload a video or leave a comment on a vide and you'll see a prompt that asks you if you'd like to start using your real name on YouTube:
When changing your appearance on YouTube, you can click Review my content to see everything you’ve posted on the site and make sure you want it associated with your new profile and full name.
If you've switched to your real name and want to change back to your username, go to your Settings page and click Revert to username in the Account Information tab. Your old username will be restored, as well as your old picture. Changes made to your privacy settings will need to be reverted manually. Switching back to a G+ name can be done by clicking Replace username with full name when using a username.
Using a real name is optional, but may be appealing to you if:
You want to keep one consistent identity across YouTube, Google, and the web. Your Google+ name and photo will appear on your existing YouTube channel.
Your old YouTube username no longer represents you or your interests; you've outgrown it and want a new username.
You'd like to use your full name on YouTube. Using your full name on YouTube will help your friends find you and your videos, and make it easier to share.
You want to access to new features that integrate Google products and services with YouTube. This includes improved sharing, live broadcasts through Hangouts On Air, and more to come.