A method of using a dual-port measurement system to measure acoustic impedance is used to measure an acoustic impedance Z of a tested object. The tested object includes an input end and an output end opposite to the input end. The dual-port measurement system comprises a first impedance tube and a second impedance tube. The first impedance tube includes a first inlet where a plane wave of a sound source is input, and a first outlet connected with the input end. The second impedance tube includes a second inlet connected with the output end, and a second outlet where the plane wave is output. The method uses the dual-port measurement system and a two-boundary method to obtain the acoustic impedances Z, whereby the dual-port measurement system is conveniently applied to various fields, such as the design of earphones, muffler tubes, sound absorption materials, and artificial ears.