A highly efficient single-photon source based on a semiconductor quantum dot(QD) is a promising candidate in quantum information processing.We report a single-photon source based on self-assembled GaAs QDs in nanowires with an extraction efficiency of 14%.The second-order correlation function g~((2))(0) at saturate excitation power is estimated to be 0.28.The measured polarization of QD emission depends on the geometric relations between the directions of PL collection and the long axis of nanowires. A highly efficient single-photon source based on semiconductor quantum dot (QD) is a promising candidate in quantum information processing. We report a single-photon source based on self-assembled GaAs QDs in nanowires with an extraction efficiency of 14%. second-order correlation function g ~ ((2)) (0) at saturate excitation power is estimated to be 0.28. The measured polarization of QD emission depends on the geometric relations between the directions of PL collection and the long axis of nanowires.