Abstract: In order to obtain high precision,high efficiency and low ripple current drivers in pump-modules of fiber amplifiers,a new laser diode (LD) driving circuit,composed of modules of driver and serial interface and so on,was designed. A switching power-converter current source based LM2676 was designed to drive LD at higher conversion efficiency.The circuit is capable of delivering up to 2.5A current to a laser load with precision of 0.1%,efficiency larger than 85% and current ripple of 0.5 mA because of a LC filter.Meanwhile long-distance reading and setting of the pump-module LD driver can be achieved by the design of serial device circuit control system.Results indicate that the circuit meets the theory design demands and can be applied in pump-modules of fiber amplifiers.