Abstract: The thermal-structure analysis of modular space deployable antenna support truss structure under space thermal alternation is studied，and reasonable protection suggestions are provided for antenna structure's influence on antenna alignment accuracy and network stability due to thermal deformation.A fine numerical model of large aperture modular spatial deployable antenna support structure was established by ANSYS APDL finite element software.Based on the existing experiments，the correctness of finite element modeling and thermal analysis model of modular deployable antenna structure was verified respectively.The influence of constraint position and other parameters on the stress and heat-induced deformation of truss chord and cable under transient temperature field is analyzed.The results show that the development of stress and deformation time history of spatial deployable antenna is basically consistent with the change trend of transient temperature field.Under the same transient temperature field，the thermal stress of the cable in the center module of the antenna structure is the largest，the thermal stress amplitude of the chords of the same circle module is basically the same，the thermal stress of the upper chord increases，and the thermal stress of the cable decreases.The cumulative thermal deformation of the antenna structure is the largest at the farthest end of the distance constraint，and the cumulative thermal deformation at the upper center point can reach about 15mm，which can not be ignored.The thermal deformation of the antenna structure is the least when the tip angle of the module closest to the center of the structure and the joint of the vertical rod with the adjacent module are used as the constraints of the antenna extension arm.In order to reduce the influence of the transient temperature field on the shape precision and deformation of the antenna structure，it is suggested to adopt thermal control coating to improve the adaptability of the antenna structure.

Key words: space deployable antenna, support truss structures, instantaneous temperature, the thermal stress, thermal deformation