In this work, a triangular silicon dimer nano-antenna structure was proposed, which can improve the fluorescence emission efficiency of the dipole source in the excitation and emission process at the same time, and realize the enhancement of far-field directional emission. The effects of the combination of the dimer, the size of the triangles right-angle side, and the spacing of the dimer on the enhancement effect of fluorescence emission were studied by using the finite difference time domain method, and the structural parameters were optimized. Finally the effect of the structure on the fluorescence excitation process was studied. The results show that the triangular silicon dimer nano-antenna structure with the right-angle side length of 300nm and the dimer spacing of 0nm are the optimal parameters of the nano-antenna. Compared with the bare light source, the fluorescence emission intensity of silicon dimer nano-antenna is increased by 7 times, and the far-field directional emission is realized. Moreover, under the excitation of 405nm wavelength light, fluorescence excitation enhancement can be achieved.