A voltage tolerance measuring apparatus configured to measure voltage tolerance of a motherboard includes a first connector configured to connect with a power connector of a computer power supply, a second connector configured to connect with a power connector of the motherboard, and a measuring circuit having an adjustable direct current (DC) power supply and a switch circuit. The adjustable DC power supply is connected to power pins of the second connector via the switch circuit. The switch circuit is connected to a power-on pin of the second connector. When the switch circuit receives a power-on signal of the motherboard via the power-on pin of the second connector, the switch circuit controls the adjustable DC power supply to supply power to the power pins of the second connector.