The preparation method is based on 2, 4-dichlorotoluene as raw material, adding a little PCl3 as catalyst, heating to 120, chlorination under the light condition, control the amount of chlorinated gas and GC for intermediate control, the main result is 2, 4-dichlorobenzyl chloride,Chemicalbook also has a small amount of 2, 4-dichlorobenzyl dichloro In addition, azodiisobutyronitrile can also be used as a catalyst, in the appropriate temperature with 2, 4-dichlorotoluene as raw material for chlorination, control the amount of chlorinated gas, and by GC intermediate control, can get 2, 4-dichlorobenzyl chloride