This root method works only on Samsung Galaxy A3 mobile running KitKat or Lollipop.
Compatible Galaxy A3 models are listed below:
- A3000
- A3009
- A300F
- A300H
- A300M
- A300YZ
Before you start, please check if your A3 model is supported by going to Settings/About Phone
Warning: Rooting voids device’s warranty. Users should proceed at their own risk.
Please note that warranty can be restored by flashing back any of the supported stock ROMs.
Root will not erase device internal storage or SD memory card, but it’s still strongly recommended to back up all data before getting started.
Prerequisites:
• The device should have at least 60% charge left on the battery.
• If you have Samsung Kies program in PC, Kies should be completely turned off to not disturb all the process.
• USB drivers must be installed on PC (if Kies are in PC then drivers are already installed).
• USB Debugging and OEM Unlocking must be enabled on the device. To enable it go to Settings/About phone and keep taping on Build number until you see Developer mode has been turned on. After that go to Settings/Developer Options then check USB Debugging and OEM Unlocking (this enables bootloader to be unlocked).
Tutorial:
1. Download to PC Odin3 v3.10.7 and extract it.
2. Download and extract CF Auto Root file depending on your device model:
A3000
A3009
A300F
A300H
A300M
A300YZ
3. Turn off Galaxy A3 and boot in to Download mode by pressing and holding down the Volume Down, Home and Power buttons together. When a warning screen is displayed release all buttons and press the Volume Up button to enter Download mode. 
4. Run Odin3-v3.10.7.exe as an Administrator and then connect Galaxy A3 to the PC via USB cable. Message showing Added!! will appear in Odin’s message box, if not, try another USB port. If the issue persists, try reinstalling the USB driver.
5. Click on the AP button and select the CF-Auto-Root file (a .tar.md5 file), which was extracted in step 2.
6. In Odin, make sure that the Auto Reboot and F. Reset Time options are checked while Re-Partition must stay unchecked. 
6.1 Click Start button in Odin to begin the process.
6.2. After the process is complete, Galaxy A3 will restart and a PASS message with green background will appear in the left box at the top of Odin. 
7. Turn off Odin and unplug USB cable from device.
8. SuperSU app will be seen on the screen.
Congratulations for successfully rooting Galaxy A3!
