Abstract: The authors presents a systematic theory and method of designing nth-order CCII (second generation current conveyor) filter with multiple-loop feedback. Various kinds of filter structures can be produced according to this theory and method. The produced filter is constructed by 2n CCIIs, n capacitors and 2n resistors. Because the input signal is only joint to circuit from y terminal of CCII, the filters have very high input impedance. Because all the RC elements are connected to ground, the filters are integrated conveniently. The design example of 4th-order Butterworth filter whose cutoff frequency is 1 MHz and its computer PSPICE simulation results are also given.