A FSS radome with high harmonic emission suppression is designed in this paper. The cell structure and size of the FSS radome are determined by the better impedance matching in the operating frequency band and better suppression of the second harmonic frequency band. Under the condition of selecting the space between the FSS radome and the antenna, the impedance, the operating frequency radiation and the second harmonic radiation of the antenna with the FSS radome are simulated. The simulated results show that the FSS radome has a little influence on the impedance and the operating frequency radiation of the antenna. The FSS radome has high suppression of the second harmonic radiation of the antenna. The suppression capability is about 10dB.