Single-photon flux is one of the crucial properties of nitrogen vacancy (NV) centers in diamond for its application in quantum information techniques.Here we fabricate diamond conical nanowires to enhance the single-photon count rate.Through the interaction between tightly confined optical mode in nanowires and NV centers,the single-photon lifetime is much shortened and the collection efficiency is enhanced.As a result,the detected single-photon rate can be at 564kcps,and the total detection coefficient can be 0.8％,which is much higher than that in bulk diamond.Such a nanowire single-photon device with high photon flux can be applied to improve the fidelity of quantum computation and the precision of quantum sensors.