The stabling center frequency technology for transmitter in wavelength devision multiplexing system is very important. The stabling center frequency technology by temperature feedback method in high speed wavelength devision multiplexing system （2.5 Gbit/s） is studied. According to the technology principle

the high precision automatic temperature controlling module for 2.5 Gbit/s transmitter has designed and experimentalized. The module has stabled the center frequency of laser diode（LD） by controlling it’s temperature. It has supplied the light source with the characteristic of stabling center frequency for wavelength devision multiplexing system application.