In order to imprve the biochemical treatment method for anaerbic fermentation liquid of swine wastewater, Chlorellaand inoculated sludge were used to construct an algae-bacteria symbiotic system. The effects of different algae-bacteria ratios (1 ∶ 0, 1 ∶ 0.2, 1 ∶ 0.5, 1 ∶ 1, 1 ∶ 5) on the growth of microalgae and the component accumulation in microalgae, as well as nitrogen and phosphorus transformation mechanisms were explored. The results showed that with an algae-bacteria ratio of 1 ∶ 0.2, the microalgae component was dominated by lipids in pure algae-cultivation system, and the concentration and protein content of microalgae in the algae-bacteria symbiotic system were 800 mg·L-1 and 56.8%. Due to the synergistic effect of algae and bacteria, the proportion of the nitrogen and phosphorusre moved by biological assimilation increased. The main pathways of nitrogen removal were biological assimilation (38%) and nitrification and denitrification (62%). The chemical precipitation (82%) and biological assimilation (18%) were the main pathways of phosphorus conversion. When the algae-bacteria ratio was 1 ∶ 0.2, the removal efficiencies of TP, TN and NH+4-N were the best, which were 76.0%, 32.7% and 31.7%, respectively. When the algae-bacteria ratio was 1 ∶ 5, the removal efficiency of soluble organic matter was the best, reaching 87.8%.