Thank You All For Your valuable Suggestions...
Below is the code i Have developed...as per My Requirement..
So the users abap and hbtabap only can view the check box and can untick that remaining all users can view this in dispaly mode..
AT SELECTION-SCREEN OUTPUT.
IF sy-uname EQ 'ABAP' OR sy-uname EQ 'HBTABAP' .
ELSE.
LOOP AT SCREEN.
IF screen-name CS 'p_chk'.
screen-input = 0.
MODIFY SCREEN.
ENDIF.
ENDLOOP.
ENDIF.