Abstract: Dual small microphone array has been extensively studied in order to increase the quality of the target speech for mobile phones, hearing aids, and other equipments which subject to space, costs and limits of computing power. Dual small microphone array speech enhancement algorithm is mainly including beamforming technique and coherence filter. The idea of beamforming technique is to use the position between desired source and the array to obtain the time-domain and space information to keep the desired direction of the signal and the other direction of the interference signal will be suppressed. Noise reduction by coherence filter is used relative signals information between microphones. Consider the advantages of these two method, this paper proposes an improved generalized sidelobe canceller(GSC) speech enhancement for dual small microphone array. The output noise of fixed beamformer(FBF) of GSC is suppressed by coherence filter to improve signal to noise ratio(SNR), and the residual noise in the fixed beamformer output can be suppressed by adaptive branch of GSC. Simulations and practical tests show that the proposed algorithm is superior to separate small array beamforming algorithms and coherence filter algorithm.