Rooting Samsung Galaxy S3 I9300
Kingo Root :download here
Root Genius :download here
Enable USB Debugging on your device.
To enable USB Debugging
Go to Setting -->> About Phone -->> And Click Several Times on Build Number -->> Go back and Developers Option is Unlocked
Step 1: Find the desktop icon of Android ROOT and double-click to launch it.
Step 2: Connect your GALAXY S3 I9300 to your computer via USB cable.
Step 3: Click ROOT to start the process when you are ready.
Step 4: ROOT Succeeded! Click Finish to reboot your device.