Cassegrain antenna can be easily installed and its structure is much simpler. However, the blind area caused by the secondary mirror costs the transmission lost. A novel transceiver antenna based on Cassegrain telescope, which makes full use of Cassegrain antenna effective area (area outside part) as transmitting, is proposed. To effectively avoid the influence of blind zone, the annular distribution and off-axis transmission of four GRIN-lens glued fiber structures transverses insteads Gaussian distribution and along-axis transmission of the lasers. The large aperture plastic fiber is used as the receiving method to improve the coupling efficiency and it makes transmitting align with receiving easily. The test results show that the transceiver antenna is easy to align at a low transmission loss costs. It satisfies the requirements of the general free space optical communication (FSO) system, and ultimately achieves transceiver integrated in one Cassegrain antenna.