The invention relates to a method for preparing arabitol by flammulina velutipes, which utilizes the characteristic that flammulina velutipes sporocarp contains rich arabitol to prepare the low-cost and environment-friendly arabitol by taking the flammulina velutipes sporocarp as a raw material; and the product can be taken as natural sweetener and functional food raw material. The method comprises the steps of: drying the fresh flammulina velutipes sporocarp, and then using high-concentration alcohol to soak or carry out reflux extraction on the dried flammulina velutipes sporocarp; carrying out vacuum concentration on the leach liquor to recover ethanol; putting the concentrated solution in the environment of 0-10 DEG C; separating out the arabitol by crystallization; filtering or centrifuging while the arabitol is cool to obtain arabitol crystal; then, carrying out recrystallization on the arabitol crystal by methanol; continuously carrying out vacuum concentration on the separated mother liquor of the crystal to recover ethanol; and repeating the operation of crystallization and recrystallization to improve the yield of the arabitol. In order to save the cost, the method is more suitable for taking defective flammulina velutipes sporocarp or the head cut from the flammulina velutipes sporocarp as raw material. The technology has the characteristics of being simple in equipment, saving the cost and protecting the environment, thus improving the economic benefit of the flammulina velutipes industry.