Thi Lo in the local language means waterfall and Su means loud, thus, Thi Lo Su means waterfall that makes a loud noise. This is due to its size and the intense flow of the stream. In Karen "Gaolian", "Thi Lo Su" means Black Waterfall. So the origin of the name is uncertain.
The biggest and the most beautiful waterfall in Thailand, Namtok Thi Lo Su is also considered the sixth biggest waterfall in the world. The waterfall itself originates from Huai Klotho, streaming along limestone cliffs at a breath of 500 meters, the height of 160-170 meters down to cascading tiers which are surrounded by intact natural forests. There is a cave behind the waterfall well worth exploring and several levels of pools for swimming.