Abstract: A new bio-carrier with large specific surface area was made by combination of both suspended carrier and solid carrier. The specific surface area of this new type of combined ball carrier was 711-1 185 m^-1 about 3-5 times as large as than that of suspended carrier. During the advanced treatment process of domestic wastewater, biofilm generated on the surface easily and fast, and microbe was advanced, abundant and difficult to be brushed off. The new carrier with 90% porosity was not easy to be plugged. It is dense biofilm on the surface and abundant protoplast growing in cavities of the zeolite that avail nitrogen removal. Experimental results show that a fluidized bed reactor with the new carrier can treat the secondary effluent very well in stable condition, after the treatment the COD_cr concentration of effluent is from 10 mg·L^-1 to 36 mg·L^-1 with a removal rate in 48%-81% and the NH₄⁺ -N concentration of effluent was no more than 2 mg·L^-1 with a removal rate of no lower than 89%. It can be concluded that water quality after treatment can meet the criterion of cooling water quality.