A multifunctional lamp mounting box includes a mounting plate defining a plurality of mounting holes; a connecting member, wherein one end of the connecting member is connected to the mounting holes, and the other end of the connecting member is connected to a mounting base; a housing, wherein an upper part of the housing is detachably connected to the mounting plate, and a lower part of the housing defines an accommodating cavity; and a lamp holder detachably mounted in the accommodating cavity and configured to connect a lamp.