TWTEG (traveling-wave thermoacoustic electric generator) is promising in efficiently converting the heat of fuel combustion, solar energy, industrial waste heat, etc. into electricity with a very scalable power output. Based on the decoupling method and theoretical analysis, the acoustic impedance requirements of the TWTE (traveling-wave thermoacoustic engine) and LAs (linear alternators) to reach an efficient and powerful operation state were studied quantitatively. A 1 kW level traveling-wave thermoacoustic electric generator was then built for experimental study. Good matching conditions of acoustic impedances were then experimentally demonstrated by modulating the working frequency, load resistance, and electric reactance of the thermoacoustic electric generator, which agreed well with the theoretical analysis. A maximum electric power output of 750.4 W and a highest thermal-to-electric efficiency of 0.163 have been achieved by the acoustically matched thermoacoustic electric generator with helium of 3.16 MPa as the working gas. This work would be instructive for the acoustic matching and designs of high-performance thermoacoustic electric generation systems.