Robert Nababan almost lost his arm when he attempted to catch the 25.6ft (7.8m) snake after discovering it on an oil palm plantation in the Batang Gansal district of Sumatra.
Undeterred by its huge size, police say he tried to capture it and stuff it into a sack.
However, the snake fought back and sunk its fangs into his left arm, nearly severing it from his body.
His life was saved when another guard and locals intervened, with one person clubbing the snake with a log.
Mr Nababan was taken to hospital for treatment after the attack on Saturday.
“The python was 7.8m long, it was unbelievably huge,” said local police chief Sutarja.
Locals later strung up the snake between two trees, before chopping it up and frying it for food.
Giant pythons are common in Indonesia and in March the body of a farmer was found whole inside one of the snakes when police sliced it open.