The invention discloses a method for improving fiber strength of hardwood pulp by utilizing compound enzyme. The method comprises the following steps: firstly, hardwood pulp pretreatment: adding carbohydrate hydrolase and a hardwood pulp board into an aquapulper which has the temperature of 35 to 40 DEG C and the pH value of 6 to 8; uniformly stirring and then adding collagenase into the hardwoodpulp under the condition of keeping the temperature unchanged to obtain pretreated hardwood pulp; secondly, adding a flocculant into the pretreated hardwood pulp, uniformly stirring and standing; thirdly, adding a charge regulator and uniformly stirring to obtain modified hardwood pulp. The modification of the hardwood pulp disclosed by the invention is realized by synergizing the carbohydrate hydrolase with the collagenase; fibers in the hardwood pulp are combined with protein and a combined substance is selectively adsorbed in the amorphous fiber region to protect the hardwood pulp; when thehardwood pulp is combined with fiber modified enzyme to treat paper pulp, the effect of selectively changing the fibers can be achieved, and further the strength of the paper is improved.