The invention discloses 3-arylcarbonyl difluorinmethylene allyl phosphonate and a synthesis method thereof. The structure formula of the 3-arylcarbonyl difluorinmethylene allyl phosphonate is shown as a following formula (1) shown as the accompanying drawing, wherein the substituent groups R1 and R2 are alkyls; or the connected R1R2 is C3-C6 alkylene; Ar is phenyl, substituent phenyl or heterocyclic aryl. Compared with the prior art, the method provided by the invention belongs to an efficient and simple method for synthesizing 3-arylcarbonyl difluorinmethylene allyl phosphonate at high-region selectivity. The method has the advantages that simplicity and convenience are realized; the conditions are mild; the yield is high; the yield of target objects can reach 65 percent to 85 percent; the region selectivity is high; the hydroacylation reaction selectively occurs on allene 2,3 site double bonds; the acyls are added onto the allene middle carbon; in addition, the palladium catalyst in the method is cheap and can be easily obtained.