Abstarct: Active regions are some parts of earth’s crust with high tectonic activities in upper Holocene and Pleistocene and will be prone to danger in future too. Geomorphological indexes are useful tools for rapid assessment of tectonic activity in a broad area. Accordingly, 7 morphometric indexes including mountain front sinuosity index (Smf), river sinuosity index (S) stream length gradient index (SL), hypsometric integral index (Hi), ratio of valley floor width to valley height index (Vf), asymmetry drainage index (Af) and Drainage basin shape (BS) were used in this research to study tectonic activity of Jajrud river located in southern edge of central Alborz. Active tectonic index (Iat) was calculated which baxsed on that Jajrud river basin was categorized in 2 class with high activity (47 % of area) and 3 class with moderate activity (53% of area) and 2 and 4 classes didn’t exist in this region. High activity classes are more coincident with Mosha fault in northern parts of this region. Multi-criteria decision making methods of AHP, SAW and TOPSIS were used to prioritize sub-basins baxsed on tectonic activity. According AHP, sub-basin of 1 and 8 (corresponding to Mosha fault and Tochal syncline) and baxsed on TOPSIS and SAW methods, sub-basin of 12 (corresponding to the junction of Mosha and north of Tehran fault) have highest level of activity.