A device and a method for optimally adjusting transmitter parameters are provided to optimize transmission performance of a digital signal system. The device comprises an error signal analyzing unit and a step length adjustment unit which are connected in signal with each other; the error signal analyzing unit analyzes an error signal and makes a determination to carry out a transmitter parameter adjustment operation; the step length adjustment unit calculates and determines an adjustment direction and an adjustment step length of the transmitter parameter; and a transmitter parameter adjusting unit carries out operations of direction adjustment and step length adjustment of the transmitter parameter according to the result of the determination.