For the existing card reader system, operating current, to some extent, is too high to use widely. To solve this problem, it is crucial to reduce the power consumption of the system. The system in this article is designed with low power consumption card reader circuit, using Holtek MCU as decoding and controlling chip, using the carrier signal of 125 kHz to finish card searching and card reading. Experimental data show that, quiescent current of the low power consumption system is approximately 5 μA, and maximum current at the time of card reading is 8 mA, which is much lower than the 1 mA quiescent current and the 15mA maximum current of the existing card reader system. Therefore, the system achieves the expected goal of reducing power consumption, and avoids replacing battery frequently. It is appropriate in the field.