The power plug includes a housing, a plurality of contact blades, a power cable, and a control circuit unit. The housing forms an interior space, which accommodates the control circuit unit therein. The control circuit unit is electrically connected between the contact blades and the power cable. The control circuit unit includes at least a rectification circuit, a voltage regulation circuit, and a timer circuit. The plug may further include a photo-control circuit, which is accommodated in the interior space and is electrically connected to the control circuit unit. As such, besides the functions of voltage bucking and timer setting, the power plug also features photo control. The power plug has a simple construction and is easy for mass production to thereby significantly lower manufacturing costs there of.