With the waste water in the closed recirculating aquaculture system as the research object, a 3-month trial was carried out by a method of natural biofilm cultivation to explore the different adsorption performances of bacteria in the wastewater treatment in the closed recirculating aquaculture system among expanded polypropylene filler (EPP), suspended ball-filler and polyurethane sponges filler; and the wastewater purification effect of NH4+-N, NO2--N and NO3--N after biofilm start-up and maturation. besides the relative indexes were also measured. The experimental results showed: EPP filler was the best for the adsorption performances of bacteria, and the other two kinds of fillers were relatively weak and had no significant difference (P<0.05); The biofilm maturation time for the three fillers was 21 d, 26 d and 30 d respectively; After biofilm maturation, during the treatment of wastewater of the closed recirculating aquaculture system, the relationship of concentrations between NH4+-N and NO2--N can be fitted with the polynomial y = ax2 + bx + c, and the relationship of concentrations between NH4+-N and NO3--N can be fitted with the logarithm y=aln(x)+b. It was concluded that these three fillers can be used as biological fillers in the closed recirculating aquaculture system.