The invention discloses a stereo-selective synthesis method for 6beta-hydroxyl-7,8-dihydro-morphine derivatives. The synthesis method comprises the following steps: (i) reducing a compound of a formula VI into a compound of a formula VII by sodium borohydride in a hydrophilic organic solvent in the presence of catalytic C1-C4 alkanoic acid; (ii) separating the compound of the formula VII obtainedin the step (i), thereby obtaining the compound of a formula VIII. Definitions of substituent groups in the formulas VI, VII and VIII are as shown in the description in detail.