Conventional diode rectifiers usually suffer from a higher conduction loss. The present invention discloses a gate-controlled rectifier, which comprises a line voltage polarity detection circuit, a constant voltage source, a driving circuit and a gate-controlled transistor. The line voltage polarity detection circuit detects the polarity of the line voltage and controls the driving circuit to turn on or turn off the gate-controlled transistor. The gate-controlled transistor may be a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) with a gate, a source and a drain or an Insulated Gate Bipolar Transistor (IGBT) with a gate, an emitter and a collector. The constant voltage source is provided or induced by external circuits and referred to the source of the MOSFET or the emitter of the IGBT. Thanks to a lower conduction loss, this gate-controlled rectifier can be applied to rectification circuits to increase the rectification efficiency.