This article studies why Rakhsh was the most known of all the horses in Shahnameh and what outstanding characteristics it had. It first deals with the importance of horses in pre-Islamic religious books and Shahnameh. Then it states that Rakhsh is a mythical horse and has humane features that are manifest in its behaviour. It feels responsible toward Rostam, likes him, understood him, and was glorious, brave, fast and unique. Its outstanding natural and animal features are also mentioned.