Agile satellites are the new generation of Earth Observing Satellites. Their agility has generated intense military and commercial interests. The biggest advantage of agile satellites is that they can reorientate themselves in a short time, and one of the research priorities for agile satellites is on reorientating them in a minimum time. For the problem of time-optimal reorientation of agile satellites, this paper reviews in detail the optimization algorithms for time-optimal reorientation and the characteristics of time-optimal solution.