A backpack structure having a lifesaving function is made of material capable of floating on water. Connection straps are provided on each end surface of the backpack, which can be buckled with connection straps of another backpack and which can be buckled with connection straps of a water bag filled with air inside. The backpack structure enables users to cross rivers more safely, so as to increase survival possibility in the field, and also to carry personnel, goods or conduct emergency relief on water.