A mounting base of a lamp, a lighting assembly, and a lamp are provided. The mounting base is configured to be in detachable connection with a plurality of lighting assemblies, the mounting base includes at least one mounting portion and a plurality of first electrical terminals fixed on the mounting portion, and the plurality of first electrical terminals on each mounting portion are configured to be in plug-in fit with a plurality of second electrical terminals of the lighting assemblies in one-to-one correspondence. The plurality of first electrical terminals are configured to supply power to the plurality of lighting assemblies when plugged in with the plurality of second electrical terminals.