Microalgae are considered as an alternative feedstock for producing biodiesel. In this study, six oil-producing algae were cultivated with natural sunlight outdoors. The highest lipid content, biomass productivity, and lipid productivity were 29.99%, 208.42 mg/l/d, and 69.84 ml/d, respectively. In addition, the photosynthetic efficiency of PS II (Fv/Fm) was kept high during the cultivation and the preferred fatty acids (C16-C18) for producing biodiesel were more than 95% of total fatty acids for all of the strains.