Disclosed is a plastic light bulb, comprising a light chip, a socket, a housing, a base and a PC bulb housing. The socket comprises a mounting part and a plug-in part, an external diameter of the plug-in part is smaller than that of the mounting part, and the light chip is installed on the mounting part; the PC bulb housing comprises a housing body and a plug, the housing body is provided with an internal space, and the plug is provided with a through hole; the mounting part is installed in the through hole, and the light chip is positioned in the internal space; and the housing is sleeved on the plug, the base is sleeved on the plug-in part, a negative electrode of the light chip is electrically connected with the housing, and a positive electrode of the light chip is electrically connected with a contact of the base.