Using scanning tunneling microscopy (STM) and low energy electron diffraction (LEED), we have studied the structural changes of the Si(100)2 x 1-Sb surface caused by hydrogen adsorption at both room temperature (RT) and 300 degreesC. We have found that the ordering of a 2 x 1-Sb surface is more stable against atomic hydrogen exposure at 300 degreesC than at RT. and that some Sb atoms desorb during atomic hydrogen exposure at 300 degreesC. However, upon hydrogen exposure at both temperatures, we have observed neither three-dimensional islands nor the hydrogen terminated Si substrate which were reported for hydrogen interaction with the other metal/Si systems. On the 2 x 1-Sb surface exposed to atomic hydrogen of 1000 L at RT followed by 550 degreesC annealing, long bright lines similar to those reported for the Bi/Si(100) system have also been found.