Abstract: In order to improve the mobility and the efficiency in combat of the 5.5 m tracking, telemetry and command (TT&C) vehicular antenna, meet the vehicle transportation requirements and reduce labor intensity, the reflector of the antenna is divided reasonably to panels. Folding mechanism between panels and high precision positioning mechanism for antenna to unfold into place are designed. The left panel and right panel rotate 180°, two edges rotate 30°, then the whole panel overturns 55°. The front panel and back panel overturn 33°and the sub-reflector rotates 158°. The antenna meets the railway and highway transportation requirements after several foldings. The reflector accuracy (RMS) is better than 0.8 mm, which is assured by means of mechanical simulation and optimization. The study changes the current situation that the TT&C vehicular antenna with deep reflector must be disassembled and assembled for transportation, realizes the auto–folding of antenna.