The impedance matching model is built to optimize the performance of the PTC from both cold finger and compressor. Based on the thermoacoustic theory, a 1-D simulation model of the 30 K PTC is built by using Delta EC softw are for optimizing the coupling w orking parameters of the cold finger and compressor. The effects of the regenerator material, the inertance tube and the reservoir on the impedance of the cold finger are investigated theoretically. The test system is set up and the results show that the low est temperature of 24. 24 K and cooling pow er of 1 W at 30 K w ith electric pow er of227 W can be obtained, w hich satisfy the applications of the space infrared detectors.