The present invention relates to a method for preparing 2,6-dichloropyridine with product purity greater than or equal to 99.0% by using trifluoromethyl chlorobenzene as a solvent for reaction between pyridine and chlorine gas. The preparation process comprises the following steps: enabling pyridine and chlorine gas to continuously experience chlorination reaction under irradiation of ultraviolet light by using pyridine and chlorine gas as starting materials and using trifluoromethyl chlorobenzene as a solvent, and cooling a chlorination reaction product and the solvent to obtain pyridine chlorination solution. Advantages: firstly, it pioneers the precedent of direct and high-selectivity preparation of 2,6-dichloropyridine through liquid phase photochlorination, and not only can the 2,6-dichloropyridine product with purity greater than or equal to 99.0% be obtained, but also industrial production is facilitated; and secondly, not only can the reuse of the separated solvent in the preparation process of the 2,6-dichloropyridine product with purity greater than or equal to 99.0% be realized, but also the purposes of low pollution, low energy consumption and low cost in the preparation process can be realized.