The invention discloses a synthetic method of a pentavalent arsenic p-type zeolite adsorbent. The synthetic method comprises the steps of mixing and uniformly grinding low-aluminum-content coal ash and sodium hydroxide particles, carrying out ultrasonic treatment, taking out the treated mixture and grinding the same, putting the mixture into an inner container of a polytetrafluoroethylene reactionkettle, adding deionized water and sodium aluminate, stirring, adequately mixing, carrying out standing on suspension liquid, putting the inner container into an electric heating incubator to carry out hydrothermal reaction, taking out the reaction kettle, naturally cooling down to the room temperature, filtering to obtain a solid product, flushing the solid product through deionized water, and drying, so as to obtain the pentavalent arsenic (As(V)) p-type zeolite adsorbent. According to the synthetic method, the adopted raw material is low-aluminum coal ash, which is a byproduct produced after the combustion of coal and contains a large number of silica and alumina, and meanwhile, the coal ash is used for being synthesized into zeolite, so that the pollution problem caused by the coal ash is solved, and the waste is turned into wealth.