The invention relates to the technical field of construction wastes, and discloses a water stability test method of a construction waste mixture stabilized by an inorganic binder. The method comprisesthe following steps: (1) a first compressive test piece and a second compressive test piece are prepared by using a mixture; (2) the first compressive test piece is put into a constant-temperature and constant-humidity curing room for curing for not less than 7 days, and the compressive test piece in the curing room is soaked into water for not less than 24 hours one day before the curing age isreached; and the second compressive test piece is put into the constant-temperature and constant-humidity curing room for curing for not less than 2 days, and the second compressive test piece is cured in water for not less than 7 days after the curing age is reached; and (3) the compressive strength of the first compressive test piece is P1, and the compressive strength of the second compressivetest piece is P2; the water stability coefficient A=P1/P2 reflects the water stability of the mixture; and the first compressive test piece and the second compressive test piece are cured differently,and the water stability coefficient is obtained by compressive strength comparison to reflect the water stability of the mixture. The test process is simple, and the operation is convenient.