A multifunctional plug, including a main body and a pin piece. The main body is provided with a holding slot for holding the pin piece. The pin piece includes a pin and a rotating shaft. The pin can rotate out of the holding slot with the rotating shaft as the rotating center, and the pin can extend into the slot of other plug and is conductive connection with the plug piece assembly of the other plug. The main body is provided with a first clamping portion, and further includes the first conductive spring piece fixed in the main body. A power adapter, including a multifunctional plug, other plug and a housing. The multifunctional plug is fixed on the housing, and the other plug is detachable and clamped on the multifunctional plug.