A variable resistance power adjustment device and lamp. The variable resistance power adjustment device includes a mounting base, keycap and resistance adjustment module. The mounting base connecting to the lamp body, working with the lamp body to form a mounting cavity in an enclosure way and provided with a through-hole connecting to the mounting cavity; a keycap connecting to the mounting base flexibly and stretching into the through-hole partially; the resistance adjustment module provided in the mounting cavity, the adjustment part of the resistance adjustment module connecting to the keycap, the resistance adjustment module connects to the driving power supply of the lamp body; the keycap moves to drive the adjustment part of the resistance adjustment module to move, so that the corresponding resistance can be switched into the driving power supply from the resistance adjustment module and the resistance adjustment module adjusts the power of the whole lamp body.