A test circuit includes a pull-up device, a pull-down device, a switch circuit and a voltage-setting unit. The pull-up device is used to receive a first control signal and coupled to a first end of the device-under-test. The pull-down device is used to receive a second control signal and coupled to the first end of the device-under-test. The switch unit is controlled by a switch signal, used to receive a testing signal and coupled to a second end of the device-under-test. The voltage-setting unit is controlled by a third control signal, used to pull the second end of the device-under-test to a predetermined voltage.