In this paper a new laser doppler anemometer (LDA), optic-electro-moduidtion-feedback LDA (OEMF-LDA), has beed described. In this system the optical components and electronic components are combined in a closed-loop by means of feedback signal which drives two Bragg cells to introduce a changable frequency difference between the two laser beams. The signal-to-noise ratio in this system is much higher than that in a conventional LDA. The frequency response of the OEMF-LDA has been discussed, based on both analysis and experiments.