The invention relates to a wastewater denitrification and dephosphorization apparatus based on capacitive deionization technique and application thereof and belongs to the technical field of three-stage treatment processes for environmental engineering wastewaters. The wastewater denitrification and dephosphorization apparatus based on capacitive deionization technique comprises a primary treatment unit, a biomembrane treatment unit, a settling tank, a cloth filter tank, a capacitive deionization tank and a cast iron pipe; the capacitive deionization tank comprises 10-30 capacitive deionization sets each of which comprises a graphite collector plate cathode, an activated carbon fiber felt electrode, a separator mesh, a graphite collector plate anode and a direct-current power supply. Effluent from two-stage treatment in a sewage plant is deeply treated through the cloth filter tank combined with the capacitive deionization technique, SS in the wastewater is removed through the cloth filter tank, and PO4<3->, NH4<+>, NO2<-> and NO3<-> are removed through the capacitive deionization tank. No chemical sludge is generated in the technique, denitrification and dephosphorization are effective, concentrate containing nitrogen and phosphorus can be recycled, and the apparatus has a promising application prospect in terms of wastewater treatment and resource recycling.