The deal gives Stanley the option to extend the deal for the 20-year-old, who has yet to make a first-team appearance for the Clarets, should they wish.
Long will go straight into the squad for Saturday's clash with Rotherham and is hoping to help push the club towards the League Two play-off places.
"I think this is the next step for me - to get out on loan, play league football and hopefully do well," he said.
"Then when I do go back to Burnley I'll improve things there so this is a great opportunity for me really.
"I was just looking at the table and I think Accrington are ninth, so they're doing really well and hopefully for the time that I'm here we can keep on improving on that."