The invention discloses a recycling method of mother liquor for SAPO-34 molecular sieve hydro-thermal synthesis, and relates to the technical field of molecular sieve synthesis. The method comprises the following steps: recovering mother liquor obtained by SAPO-34 molecular sieve hydro-thermal synthesis crystallization and separation, additionally adding a silicon source, an aluminium source, and a phosphorus source into the mother liquor used as a raw material, mixing, adding a substrate material, a binder, and a pore forming agent, preparing microsphere raw powder by spraying molding, putting the roasted microspheres and an aqueous solution of an organic template together into a stainless steel reaction vessel, performing in-situ crystallization to prepare a spherical SAPO-34 molecular sieve catalyst which can be used directly in a fluidized bed device.