An electronic device packaging box includes a first base, a second base and a connecting unit. The first base includes two side walls spaced apart from each other in a first direction and each having a first side receiving space, and a connecting wall interconnecting the side walls to define a receiving space. The second base is received in the receiving space, and includes spaced-apart top and bottom walls, and a separating wall interconnecting the top and bottom walls to define two second side receiving spaces. The connecting unit includes two first connecting subunits, each of which is mounted to a respective one of the side walls, and two second connecting subunits, which are mounted to the bottom wall.