The invention relates to a method for preparing 4-chloro-3-methoxy-2-methyl-1H-pyridine. Triphosgene is used to chloridize a raw material 4-chloro-3-methoxy-2-methyl-1H-pyridine as a chloridizing agent, so generation of phosphate solids and phosphorus-containing wastewater in the post-treatment process is avoided, and the environment protection pressure of enterprises is reduced; condition optimization makes the product yield reaches 95% or above and makes the purity reaches 97% or above, so the market competitiveness of the enterprises is improved; and triphosgene has low toxicity, so the method has the advantages of simple operation, low apparatus requirements, no strict condition of anhydrous conditions, and good safety. The above new method meets safety, environmental protection and economy requirements of industrial production.