The invention relates to a low power consumption method of a wireless sensor network and a wireless sensor node. In the method, the wireless sensor node comprises a processor, an FPGA (field programmable gate array) chip, a first radio-frequency circuit and a second radio-frequency circuit, wherein the processor is electrically connected with the FPGA chip; and the first radio-frequency circuit and the second radio-frequency circuit are electrically connected with the FPGA chip respectively. The frequency range of the first radio-frequency circuit is different from that of the second radio-frequency circuit, namely that the first radio-frequency circuit is specially used for transmitting data, and the second radio-frequency circuit is specially used for synchronizing the nodes of the wireless sensor network and transmitting an acknowledgement frame; and the information transmitted by the first radio-frequency circuit and the second radio-frequency circuit does not conflict with each other. In the invention, by working in double frequency ranges, the nodes of the wireless sensor network are synchronized, the data conflict is reduced, the data transmission is efficient, and the power consumption of the nodes is reduced.