Personal hotspot device with a wifi power control function and method therefore

A radio communications power control method which can be applied in a hot spot device acquires a first signal power and a first noise power of a first channel by which the hot spot device communicates with a base station, and calculates a first signal-to-noise ratio between the first signal power and the first noise power. The device acquires a second signal power and a second noise power of the first channel when the hot spot device functions, and calculates a second signal-to-noise ratio between the second signal power and the second noise power. A difference is calculated between the first signal-to-noise ratio and the second signal-to-noise ratio, and if the second ratio is greater than the first ratio by a preset reference value, a power of the electromagnetic wave of the hot spot device is reduced to a target value.