This paper make a deep research on the power supply system of national automatic weather stations, designs the alarm circuit, lifespan check circuit and remote monitoring computer software to monitor the battery condition and improve the design defects through slight controlling the battery charge and discharge. The system, using the freescale high performance processor and the highside current detection circuit with AD8210 as the core, detects the microcurrent of the shunt resistance to prevent overcharge and over discharge, which harms the battery life. The information including AC power off alarm, voltage, battery life, charging interval, etc, is transferred to the computer software through the acoustooptic alarm circuit and data communication circuit, which reminds the observer and at the same time makes automatic charge and discharge maintenance every three months with RTC clock module. The battery life is extended and the waste is reduced.