The invention belongs to the technical field of organic chemical industry, and relates to a continuous preparation method of an important intermediate pyridone chloride adduct of 2-chloro-5-methylpyridine, in particular to a method for synthesizing the pyridone chloride adduct by taking pyridone and chlorine gas as raw materials, and further synthesizing the 2-chloro-5-methylpyridine, with the stable total yield of 93% or above. The method is characterized in that microchannel continuous reaction is adopted, so that the method has the advantages of relatively high reaction selectivity, no backmixing, low production cost, less equipment investment and a safe and environment-friendly production environment.