The invention discloses a 4-halogenated-2-methyl-2-ethyl crotonate preparing method which includes following steps: (1) performing a Grignard reaction to ethyl pyruvate (II) and a vinyl magnesium halide Grignard reagent (III) to obtain a condensation compound (IV) after the reaction finished, and carrying out a hydrolysis reaction to the condensation compound (IV) to obtain a hydroxyl compound (V); and (2) performing a halogenating reaction to the hydroxyl compound and a haloid acid to obtain the 4-halogenated-2-methyl-2-ethyl crotonate (I). The 4-halogenated-2-methyl-2-ethyl crotonate preparing method is simple in total technology, allows raw materials to be obtained easily, is good in reaction selectivity, is less in by-products and is high in yield. The employed raw materials are all low-toxic or toxic-free and are all corrosiveness-free so that the method is not rigorous in requirement of devices, is environmental-friendly and is suitable for industrialized production.