The invention discloses a paper-aluminum-plastic composite bag for medicine external packaging. The bag comprises a printing layer, an external film layer, a first adhesive layer, an aluminum foil layer, a second adhesive layer and a heat-sealing layer which are sequentially arranged from outside to inside. The first adhesive layer and second adhesive layer respectively comprise the following components in parts by weight: 5-10 parts of dimethyl sebacate, 2-5 parts of melamine, 5-15 parts of polyvinyl adhesive, 1-3 parts of chinlon fiber, 1-3 parts of hydroxypropyl methylcellulose, 10-15 parts of 905 emulsion, 10-15 parts of chloroprene rubber, 5-8 parts of butylbenzene, 5-8 parts of styrene, 2-6 parts of corn starch, 10-15 parts of metal bamboo charcoal solution and 2-5 parts of acetic acid. The layers have high binding force, so the bag has favorable service performance.