Abstract: In order to optimize the design of wide field-of-view high-gain optical antenna in free space, the finite element method was utilized to analyze the effect of different structure parameters on transmission enhancement characterization of bull's eye structure, horn-shaped structure and bowl-shaped structure respectively. The relationship between the numbers of slit and the coefficient of surface-plasmon-enhanced extraordinary transmission was obtained, and the optimal structure parameters of bowl-shaped optical antenna with subwavelength structure was gotten. The results show that for horn-shaped optical antenna, when the single silt can excite the strongest surface plasmon polaritons(SPP), the coefficient of transmission enhancement has lager value. By optimizing the structural parameters, the value of horn-shaped structure enhancement coefficient varies from 20 times to 140 times when the incident angle θ is within ±5°. The smooth enhanced gain is gotten at the incident angle in the range from ±5°to ±26°. The average value of the enhancement coefficient is 10. The performance is doubled compared with the performance of present structural parameters. Bowl-shaped structure has a good enhanced transmission character at the incident angle in the range of ±60° and the average value of the enhancement coefficient is 10 in the smooth enhanced transmission area. The wide field-of-view transmission character of the bowl-shaped is better than of the horn-shaped.