Replace Kingroot with Supersu

• First of All, Install Terminal Emulator in your Android Phone, if you haven’t installed it already.
• After that, Extract Zip file in root of your SD card & in Internal Storage both, which you was downloaded from above Link, named as Replace_Kinguser_with_SuperSU-v2.4.zip
• After that, Open Terminal Emulator in your Phone & Type Below Commands one by one & hit enter

su

• After Enter above Command, it will ask you for Root permissions, Allow Grant Root permissions & Enter below command.

sh /sdcard/mrw/root.sh

• Now, it will start running script & you have to wait for some time, approx 1-2 minutes, make sure your mobile data is turned on.[may be Sync Online]
• After it’s Done, Now Open your App Drawer, & you will see there is the super su app come. Just open it
• Now, it will ask you for update Superuser binary, Click on Continue button & Select Normal Mode
• It may ask you that, other party root apps are already installed, so you have to click on OK button & it will remove Kingroot app from your phone & Supersu app will come & you are done ! 

from : http://alltrickszone.com/replace-kinguser-kingroot-supersu-superuser-android-guide/