A lamp module includes: a single piece of a mounting base including an arcuate mounting plate defining two retaining recesses, and a bracket extending upwardly from the mounting plate; two socket units mounted respectively on two opposite ends of the bracket, each of the socket units being formed with pin holes adapted to receive pins of a fluorescent tube; an arcuate reflective plate having two opposite lower ends received in the retaining recesses in the mounting plate; and a pair of connectors provided on the sockets units and having pins for insertion into pin holes in sockets of a ceiling lamp suspending holder.