The paper designes a new ultra-low power auto gain control amplifier, and analysis the structure and working principle of it. Different form common auto gain control amplifier, this system need to remain stable work in harsh environments and work with ultra-low power consumption. Thus, we use wake-up module and decay resistance network with high linearity; moreover, most MOSFETs in all analog circuits are designed to work in sub-threshold region. And we demonstrate that the design is practicable by setting up simulation platform. The simulation result shows that, the presented receiver can operate in the environment of -40℃-125℃ temperature range and 2.3V-5V supply voltage range with ultra-low power consumption, and its operation is stable and reliable.