A paper box assembly includes at least one first box, at least one second box and at least one connecting piece. The at least one first box includes a plurality of first plates and at least one first slot. The at least one second box includes a plurality of second plates and at least one second slot. The at least one connecting piece includes a first insert, a second insert and a bendable connecting portion. Two insertion spaces formed on the bendable connecting portion and defined between the first insert and the second insert. The first insert is inserted into the first slot. The second insert is inserted into the second slot. Thus, the at least one first box and the at least one second box are connected by the at least one connecting piece.
