The invention relates to a two-step etherification synthesized s-triazine ultraviolet absorbent UV-1577. The two-step etherification synthesized s-triazine ultraviolet absorbent UV-1577 is prepared by the following steps: utilizing a raw material (shown in the description) 2-(2,4-dihydroxyl)-benzo-4,6-diphenyl s-triazine and a raw material (shown in the description) alkali metal or alkali earth metal hydroxide to react in a water carrying agent at a specific temperature to obtain an intermediate product, removing, by steaming, the water carrying agent, cooling to room temperature, adding N,N-dimethyl formamide (DMF) to react with bromohexane at 70 DEG C to obtain the s-triazine ultraviolet absorbent UV-1577. The preparation method is divided into two steps, compared with the existing production process for synthesizing the UV-1577 in one step, the generation of inorganic salts is reduced, a high-temperature salt pressing link is eliminated, the unsafety factor of the operation by workers can be reduced, and the two-step etherification synthesized triazine ultraviolet absorvent UV-1577 has the characteristic of environmental friendliness, and has the advantaages of simple equipment, advanced technology, convenient operation, capability of cooperatively using a solvent, low cost and easy industrialized production, and the purity of a liquid phase is greater than 99.3 percent.