The invention discloses a molecular complex, which is formed by taking albumin or tumor targeted group modified albumin as a drug carrier and by loading anthracycline anticancer drug molecules in a natural 'pocket' of the albumin by virtue of a molecule encapsulation method. With the implementation of the complex, the in vivo tumor targeting capacity of the anthracycline anticancer drugs is enhanced and an anti-tumor effect is improved; and in addition, cardiotoxicity is significantly reduced and a therapeutic window is improved.