The invention provides an off-chip driver, which comprises a first driving circuit used for adjusting the slew rate of the off-chip driver. The first driving circuit comprises a first pre-driver, a switch string and a first output stage. The first pre-driver receives a read signal and a first pre-driver control signal. The switch string is configured to perform a voltage division operation on thepower supply voltage according to the read signal in combination with the first pre-driver to generate a first output stage control signal. The first output stage generates a data signal according toa first output stage control signal.