Nam Tok Sai Khao National Park covers Amphur Kok Pho, Pattanee province, Amphur Sabayoy Songkla province, Amphur Yaha and Muang Yala Province, with an area of about 110 km2. The topography is mountainous in San Kala Kiri mountain ous range, covers with fertile moist evergreen forests, it is headwater of many rivers flow to Tepa River.
The park is located on a complex Sangalakiri mountain range with its summit of Bang Chun mountain. Most of the area slopes down westward from the mountain as a hill and plain. Soil characteristic is clay mixed with sand and stone characteristic is limestone and granite stone.
Rainy season is under influence of southwest and northeast monsoon starts from May to January causing abundant rain over this area (particularly in October-December). Summer starts from February to Aril and it is not too hot.