As aerospace telemetry missions require more mobility and protection, large vehicle-mounted telemetry antennas have begun to be installed in square cabins, which can be stored properly during transportation and deployed during work, and can be able to fulfill communication requirements in vehicle movement. The shelter roof opening mechanism is mean to suppress the environment factors such as wind, sand, rain and snow, to improve the working conditions, and to increase the reliability of telemetry antennas. In order to meet the antenna working requirements, the shelter roof opening mechanism can open and close automatically. And the storage state can keep the large telemetry antenna from rain, dust and unexpected impact for protection. Due to the limitation of the size and the transportation of large telemetry antenna, the traditional shelter roof opening mechanisms lack of design space and self-protection. Therefore, this paper introduces a new type of shelter roof opening mechanism for large vehicle-mounted telemetry antennas. In this mechanism, the shelter roof is divided into two parts from the left to right, and the two parts unfolds following their own direction. And the upper left and right cabin walls moves along with the shelter roofs. When the shelter roof mechanism opens to the limit, they ply-up with the left and right cabin walls. Hence, the total width of the shelter roof mechanism hardly increases, which guarantees the road transportation of the telemetry antenna. The shelter roof opening mechanism adopts electric push rod and wire rope winch to achieve automatically open and close. The mechanical analysis and selection of electric parts are introduced in this paper. The new shelter roof opening mechanism not only realizes the automatic opening and closing, but also meets the communication requirements of the large telemetry antenna in vehicle movement with effective protection. Finally, the shelter roof mechanism has been proved to show favorable application results in practice.