It is crucial to enhance the far-field directional emission of quantum dots (QDs) in order to improve the sensitivity of bio-detection. In this paper, we propose a novel and effective photonic structure composed of periodically distributed silver nanodomes on a SiO2 film and silver back reflectors. The radius of each nanodome structure is 162.5 nm, and the QD is located in the gap between adjacent silver nanodomes. The finite-difference time-domain (FDTD) method is used to investigate the effect of different QD positions and different quantities of nanodomes on the emission intensity of QDs. The results show that when there are four nanodomes and the QD is located in the gap between adjacent nanodomes, the emission intensity of QDs in the far field is improved by more than four times compared to that of the nanodome free structure. The proposed structure will improve the sensitivity of biological detection.