Abstract: A first aspect of the present invention provides a method for the preparation of 2-chloro-5-chloromethylpyridine, comprising: performing a cyclization reaction on 4,5-dichloro-4-methoxypentanenitrile in presence of a silicon compound and an acylamide compound to obtain 2-chloro-5-chloromethylpyridine. Another aspect of the present invention provides a method for preparation of 2-(chloromethyl)-5-(trifluoromethyl)-1,3,4-oxadiazole, comprising: performing a cyclization reaction on 1-(chloroacetyl)-2-(trifluoroacetyl)hydrazine in a presence of a silicon compound and an acylamide compound to obtain 2-(chloromethyl)-5-(trifluoromethyl)-1,3,4-oxadiazole. The silicon compound or/and acylamide compound provided by the present invention serve as cyclization reagents and have high efficiency.