The invention relates to trans alpha-acyl-beta, gamma-unsaturated carboxylic ether and a synthesis method thereof. The method comprises the following steps of: carrying out a 1,4-addition reaction between a Grignard reagent and allenes acid ester under the action of a catalyst of acetylacetone iron at a temperature of 78 DEG C below zero to generate a 1,3-conjugated diene magnesia salt; and carrying out a reaction of the Grignard reagent and allyl alcohol ester of various acids to produce a series of trans alpha-acyl-beta, gamma-unsaturated carboxylic ether compounds. An operation of the synthesis method is simple, raw materials and reagents are easy to obtain and reactions have high regioselectivity and stereoselectivity, two substituents can be introduced at the same time, and the product is easy to separate and purify, thereby being suitable for synthesizing various substituted trans alpha-acyl-beta, gamma-unsaturated carboxylic ether.