Photosynthetic mitigation of CO 2 with microalgae is promising from many aspects, thereby becoming a popular research topic. In this study, seven out of twenty-two indigenous Scenedesmus obliquus isolates obtained from southern Taiwan were selected for detailed study on their CO 2 fixation ability. Among them, 2 strains, namely, S. obliquus CNW-N and AS-6-1, displayed high cell growth rate and CO 2 removal ability when they were grown on 20% CO 2 . The 2 strains show a high specific growth rate of 1.019 and 1.065d −1 , respectively, along with a high biomass concentration (2.63 and 1.90gL −1 , respectively). The biomass productivity of S. obliquus CNW-N and AS-6-1 was 201.4 and 150.7mgL −1 d −1 , respectively and the CO 2 consumption rate could reach 390.2 and 290.2mgL −1 d −1 , respectively, which are higher than that reported by most relevant studies.