ALTERNATOR WAS REPLACED BUT BATTERY STILL GOING DEAD on 2001 Ford Explorer

ALTERNATOR WAS REPLACED BUT BATTERY STILL GOING DEAD ALSO IF I DISCONNECT NEGATIVE CABLE ENGINE TURN OFF

2 answers
Never ever ever disconnect the battery while the car is running. You can and will damage components.

Sounds like the battery itself may need replacing as it is. Charge and/or replace the battery and retest your electrical system.
I need to know how to replace the alternator, and take off belt