The invention relates to a zero-voltage control circuit for small signals. The circuit comprises a first operational amplifier, a second operational amplifier, a third operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a first transistor, a first exclusive-OR gate, a second exclusive-OR gate, a third exclusive-OR gate, an optical coupler, a first power source and a second power source. The zero-voltage control circuit for the small signals achieves zero-voltage detection on the small signals, detection accuracy is high, various isolation protection means are adopted, and therefore no interference will happen to an external circuit, the signal deviation problem does not exist, and zero-voltage control over data output is achieved well.