I solved it with my own effort.
function bp_remove_nav_item() {
$current_user = wp_get_current_user();
$role_name = $current_user->roles[0];
if($role_name==='administrator'){
bp_core_remove_nav_item( 'buddyblog' );
}
}
add_action( 'wp', 'bp_remove_nav_item' );
This code delete blog menu for administrator.