[Objective] The aim of this study is to isolate Chlorella vulgaris(chlorella)and extract its genomic DNA.[Method] Both the dilution method and drip method were employed to isolate chlorella from lake water samples;the conditions for culturing chlorella were optimized and its genomic DNA was extracted by improved CTAB method and SDS method.[Result] The proper conditions for chlorella culture were as following:temperature 20-25 ℃,illumination 4.39-5.86 W/m2 and rotational speed 100-150r/min;improved CTAB method was suitable for extracting genomic DNA from chlorella.[Conclusion] The study is helpful to study the chlorella at molecular level and promote the exploitation and utilization of chlorella resources.