The invention relates to a process for synthesizing N-caprylyl benzotriazole. The process comprises the following steps: dissolving benzotriazole and alkali into a dry solvent, dropping caprylyl chloride at 20-120 DEGC for 2-6 hours, after dropping, keeping the temperature of 20-120 DEGC to react for 3-15 hours, cooling to the room temperature, washing twice with water, adjusting the pH value to 7-10 by using a 1-10% sodium hydroxide solution, washing with water once again, leaving to stand to layer, performing depressurized concentration, and recycling the solvent, thereby obtaining a target product; applying the received solvent mechanically to next reaction after being dried, wherein the mole ratio of benzotriazole and alkali to caprylyl chloride is 1:(1.0-2.5):(1.0-2.0), and the volume mass ratio of the dried solvent to benzotriazole is (1-10):1. Compared with the prior art, the process is not only good in product quality, stable to operate, small in amount of wastes and low in production cost, but also high in purity and high in yield.