Abstract:[Objective] In order to research the characteristics of artificially constructing algae symbiosis system in oil production. [Methods] aseptic Chlorella was screened and isolated from the BG11 medium, the growth and oil-producing characteristics of Chlorella in the symbiosis system were studied by artificial construction of co-culture system of algae and bacteria. [Results] The results showed that the growth of algae, accumulation of oil and the production of fatty acid components of biodiesel were significantly higher in the co-culture system of algae and bacteria compare to that of aseptic Chlorella. Co-culture system of bacteria (Stenotrophomonas maltophilia) and Chlorella has the best effect, and the biomass, oil content and C18-1 of Chlorella increased by 9%, 36.3% and 259.2% respectively. [Conclusion] This study shows that the quality of microalgae biodiesel with good utilization value can be improved by artificial construction of co-culture system of algae and bacteria.