The invention provides a processing method for citric acid sludge, specifically a preparation method for glucosamine hydrochloride from the citric acid sludge. The method mainly comprises: separating citric acid mycelium from the citric acid sludge, after breaking walls, hydrolyzing with low-concentration acid, separating and obtaining glucosamine hydrochloride. The method takes plants as the raw materials, and is wide in applicable groups, mild in conditions of the whole method, high in utilization rate of the raw materials, low in acid consumption, none in charring phenomenon and less in environment pollution.