Rhodiola sp. (R. heterodanta and R. imbricata), belonging to the stone crop family Crassulaceae, is an important medicinal plant and food crop in Trans-Himalayan cold desert. It is a well known medicinal plant in the Amchi system of medicine (Tibetan system of medicine) being used in various ailments like anti-stress, radio-protective, anticancer, anti-inflammatory agent, adaptogen etc. Hydro- alcoholic extracts of Rhodiola sp. root and shoot were investigated in the present study to quantify total Phenolic as well as anti-oxidant activity. Total phenolic contents were determined as total flavonoids (TF), and total polyphenols (TPP). Rhodiola heterodanta root extract had highest amount of total phenol and flavonoids are found to be 79.21±.26 mg GAE/g and 269.3±.82mg Qc/g respectively. In vitro antioxidant activity was investigated by DPPH radical scavenging activity, reducing power assay. R. imbricata hydro-alcoholic root extract showed the highest reducing power and DPPH. radical scavenging. A significant correlation existed between concentrations of the extract and percentage inhibition of free radicals and reducing power. These results clearly indicate that Rhodiola sp. are effective against free radical mediated diseases and also helpful to draw special attention for further studies.