The invention relates to an ortho-position dihalogen substitution compound of aryl pyrimidine and a preparing method thereof. The compound has the following structural formula I: R1=H, p-Me, p-Cl, p-COOEt, p-CF3, m-Me, m-OMe, R2=H, 4-Ph, 5-Ph, X=Cl, Br. The invention comprises the following steps: dissolving aryl pyrimidine, palladium acetate, additive and halogenation calcium into acetic acid, stirring, and reacting until reaction raw material disappears; removing solvent, adding saturation sodium bicarbonate solution into a system, and extracting a product with ethyl acetate; obtaining a crude product by drying the organic phase and removing the solvent; purifying the product to obtain the corresponding ortho-position dihalogen substitution compound of aryl pyrimidine. The compound of the invention is a kind of important organic synthesis intermediate. The invention has easily obtained raw material, high reaction selectivity, and adopts calcium chloride and calcium bromide with low price as a halogen source, uses common solvent in reaction, and has simple operation, moderate reaction condition and environmentally friendly reaction, maximum reaction yield can reach 95%, so that the invention is very suitable for industrial production.