The invention discloses a fly ash leaching solution treatment method and system. The fly ash leaching solution treatment method comprises the following steps: adjusting the pH of a leaching solution to be 8 to 11 in a primary reaction tank, then feeding the leaching solution in various reaction tanks, separately adding a heavy metal chelating agent and a flocculating agent, generating alumen ustumparticles, standing, precipitating, adjusting the pH to 3 to 5, adding a Fenton reagent, standing, precipitating, introducing supernatant into a purification tank, purifying the supernatant, treatingby using a membrane treatment unit, thus obtaining reverse osmosis production water and a reverse osmosis concentrated solution, wherein the produced water is good in quality, the produced water is recyclable, evaporating and crystallizing the reverse osmosis concentrated solution by virtue of an evaporation unit, recycling salt substances, wherein the recycled salt substances can be used for producing industrial salt. The treated solution can be recycled, so that the zero emission of waste water can be realized; the crystal salt can be produced; the fly ash leaching solution treatment methodis an environment-friendly, safe and efficient treatment method, the environment pollution problem caused by the fly ash leaching solution produced after the garbage is incinerated can be solved, thesystem operation is simple, the equipment requirement is simple, and the system operation is reliable.