In my Drupal database I have so many field_deleted_data_XX and field_deleted_revision_XX tables. I have disable the revision entity but I want to delete these existing revision created tables, can I delete these tables directly or Is there any SQL script to delete unused tables from the database.
You can safely remove them yes. You can use drush to delete these tables: run
drush eval 'field_delete_field("yourfield")' and run cron afterwards with