There is no parry in Street Fighter IV. Something similar is
Focus attack doesn't require a perfect timing which you need in parry. Also, you can`t parry all upcoming attacks and you are not invincible when doing it. To do a Focus Attack, press and hold Medium Punch + Medium Kick at the same time and your character will start charging. There are a lot of differences between focus attack and parry:
- Focus attack is an offensive move that can stun the opponent. It has three different "levels" depending on how long you've held it and only crumples ("stuns") if it's a counterhit (level 1), unblocked (level 2), or always (level 3).
- Focus attack doesn't completely negate the damage, you absorb it into your health bar as recoverable health. You should not focus when low on life, as you will die if you take 200% of your current HP as "recoverable" damage.
- You can only focus one attack, so moves which hit twice or just a couple of jabs or short will be able to penetrate the focus.
- Throws, command grabs, and many ultras and specials that are called armorbreakers which will hit you regardless of focus. When this happens you'll hear a sound like a pane of glass shattering.
In order to cancel the Focus Attack, right after the parry, for instance, keep Medium Punch and Medium Kick pressed down and dash forward or backward.
If you land a L3 focus attack or any other focus that crumples, you should immediately dash towards your opponent and execute your most powerful combo, ultra, etc. This is a great chance to deal damage.