Focusing on the human computer interaction(HCI) real scenarios, a method for acoustic source three-dimensional localization and speech enhancement is proposed. Combining with the receiver model of six microphone parallel uniform linear array (ULA), the target acoustic source is located in three dimensions based on the method of time-difference of arrival (TDOA) estimation improved from generalized cross correlation (GCC).On the basis of positioning the target acoustic source, the target speech enhancement is implemented by the method of delay-and-sum beamforming (DSBF). Simulation results show that the method can position the target acoustic source accurately and enhance the target speech effectively. In the context of SNR greater than 1.5 dB,the positioning accuracy of the target acoustic source can reach more than 98% and improvement of SNR can reach 5 dB with less computation cost and easier hardware implementation.