The invention relates to a flexible cable stretching rod device comprising a plurality of secondary flexible cable stretching rods 2, a cable synchronization part 32 and a control motor 18. The secondary flexible cable stretching rods 2 are arranged by taking a satellite spinning axis as a symmetrical center, and the cable synchronization part 32 is used for controlling all the secondary flexible cable stretching rods 2 to be released synchronously in equal length. Each secondary flexible cable stretching rod comprises a flexible cable 6 and a winding shaft portion 9 used for winding the flexible cable 6, the winding shaft portion 9 further comprises a cable coil center shaft 33 and a cable winding shaft 23 coaxially fixed with the center shaft, and the cable winding shaft 23 is supportively fixed on the side wall of an L-shaped support 7 via a winding shaft support 10; one segment of each flexible cable 6 is wound on the cable winding shaft 23, and the other segment of each flexible cable 6 reaches a starting point retainer 13 via a cable limiter 16, a cable pressing wheel pair 20 of the cable synchronization part 32 and a cable protection tube 11 below the flexible cable; the L-shaped support 7 is located in the middle of a loading chamber floor 3.