OBJECTIVE： To study the antioxidant activity of Rhodiola rosea extract and salidroside in vitro. METHODS： The anti-oxidative activity of R. rosea extract （0， 10， 20， 30， 40， 50， 60 mg/L） and salidroside were compared， using strong antioxidant VC or 2，6-di-tert-butyl-4-methylphenol （BHT） as control， by ·OH radical clearance rate， DPPH free radical scavenging rate， H2O2 clearance rate， oleic acid antioxidant capacity and Fe3+ reduction ability test. RESULTS： R. rosea extract and salidroside could clear up ·OH radical， H2O2 and DPPH free radical to different extents， with the clearance strength order as R. rosea extract＞VC＞ralidroside； when the concentration of them was 60 mg/L， clearance rates of them to ·OH radical， H2O2 and DPPH free radical were 92％， 81.33％ and 79.51％； 83.76％， 72.69％ and 57.29％； 43.70％， 37.30％ and 28.53％， respectively. In oleic acid antioxidant capacity test， antioxidant capacity was in descending order as R. rosea extract＞BHT＞salidroside. In Fe3+ reduction ability test， reduction ability of R. rosea extract was better than salidroside under the condition of same concentration； Fe3+ reduction rate of R. rosea extract and salidroside were 43.63％ and 16.18％ when their concentration reached 60 mg/L. CONCLUSIONS： Both R. rosea and salidroside show good antioxidant activity in vitro， but the antioxidant activity of R. rosea extract is better than that of salidroside， indicating other components of R. rosea extract may play a leading antioxidant effect besides salidroside.