A packaging box, comprising: a body having an accommodating space and a bottom opening communicating with the accommodating space, and comprising a first side plate and a second side plate opposite to each other and a third side plate and a fourth side plate opposite to each other; a first bottom plate foldably connected to the first side plate and having a first bottom part for covering the bottom opening and a main inserting part foldably connected to the first bottom part, wherein the first bottom part has a slit, and when the first bottom part covers the bottom opening, the main inserting part is adapted to be inserted into the bottom opening to contact with the second side plate; and a second bottom plate foldably connected to the second side plate and comprising a second bottom part and a tongue extending from the second bottom part, wherein the second bottom part of the second bottom plate is adapted to be superposed on a portion of the first bottom part, and the tongue is adapted to be inserted into the slit, so that the second bottom plate is detachably fixed to the first bottom plate, wherein the packaging box is characterized in that the packaging box further comprises two side bottom plates respectively foldably connected to the third side plate and the fourth side plate, the two side bottom plates are adapted to be superposed on a portion of the first bottom part, and the second bottom part is adapted to be superposed on a portion of the first bottom part and portions of the two side bottom plates and wherein the first bottom part has a first edge and a second edge opposite to each other, and the first bottom plate further comprises two secondary inserting parts respectively foldably connected to the first edge and the second edge of the first bottom part, and, when the first bottom part covers the bottom opening, the two secondary inserting parts are adapted to be inserted into the bottom opening to contact with the third side plate and the fourth side plate. a body having an accommodating space and a bottom opening communicating with the accommodating space, and comprising a first side plate and a second side plate opposite to each other and a third side plate and a fourth side plate opposite to each other; a first bottom plate foldably connected to the first side plate and having a first bottom part for covering the bottom opening and a main inserting part foldably connected to the first bottom part, wherein the first bottom part has a slit, and when the first bottom part covers the bottom opening, the main inserting part is adapted to be inserted into the bottom opening to contact with the second side plate; and a second bottom plate foldably connected to the second side plate and comprising a second bottom part and a tongue extending from the second bottom part, wherein the second bottom part of the second bottom plate is adapted to be superposed on a portion of the first bottom part, and the tongue is adapted to be inserted into the slit, so that the second bottom plate is detachably fixed to the first bottom plate, wherein the packaging box is characterized in that the packaging box further comprises two side bottom plates respectively foldably connected to the third side plate and the fourth side plate, the two side bottom plates are adapted to be superposed on a portion of the first bottom part, and the second bottom part is adapted to be superposed on a portion of the first bottom part and portions of the two side bottom plates and wherein the first bottom part has a first edge and a second edge opposite to each other, and the first bottom plate further comprises two secondary inserting parts respectively foldably connected to the first edge and the second edge of the first bottom part, and, when the first bottom part covers the bottom opening, the two secondary inserting parts are adapted to be inserted into the bottom opening to contact with the third side plate and the fourth side plate.