A method for preparing Aliskiren and intermediate thereof, which comprises the following steps: reacting 4-bromo-1-methoxy-2-(3-methoxypropoxy)benzene with magnesium isopropyl chloride and n-BuLi to obtain the compound of formula XXII; reacting the product of methylsulfonylation of the compound of formula XIX with anhydrous LiBr to obtain the compound of formula XXI; obtaining the intermediate of Aliskiren shown as formula XV by reacting the compound of formula XXII with the compound of formula XXI in an ether as the solvent and in the presence of a catalyst containing iron; then reacting the compound of formula XV with the compound of formula VII to obtain the compound of formula XXIII, following removing R1 from the amino group and obtaining Aliskiren shown as formula I.