In order to solve the technical problem of bearing load on both ends of the optical antenna, a loadable laser communication optical antenna for satellite platform was proposed, and at the same time guaranteed the imaging quality of the one point to multi-point laser communication terminal optical antenna. In order to ensure the surface accuracy of the primary mirror and the position accuracy of the secondary mirror, the structure and connection form of the primary mirror assembly, the loadable baffle and the secondary mirror support truss were optimized. Using ANSYS finite element analysis software for analysis, the results show that the first-order mode frequency of this structure is 151.54 Hz; The front end of the optical antenna can carry the quality of 8.5 kg and the rear end of the antenna can carry the quality of 13 kg; Under the condition of 1 g radial self-gravity and bearing load at both ends, the RMS(root mean square error) value of surface shape error of the primary mirror is λ/158, PV(maximum peak-to-valley error) value is λ/30, the maximum inclination of the secondary mirror is 1.88″; Under the condition of (20±5)℃ ambient temperature, 1 g axial self-gravity and bearing load at both ends, the RMS of the primary mirror is λ/65 and the PV is λ/14, the maximum inclination of the secondary mirror is 1.21″. It shows that the antenna has good mechanical properties, thermal properties and imaging quality after being loaded. It can meet the requirements of the antenna in the installation, detection and transmission of the ground. The ZYGO interferometer was used for testing. The quality of the load and the position of the center of gravity were simulated by the mass. The results show that the system wavefront aberration of the system RMS can meet the index requirements of λ/15 under the condition of 1 g gravity and load.