The invention discloses a gas extraction device in a coal mining area. By setting a high frequency oscillator, the gas can be completely extracted and the gas flow can be promoted. In the process of gas extraction, a plugging assembly is firstly used to mount and position an extraction pipe and after well plugging, good sealing performance is ensured; later, an extraction pump is used, a control valve is controlled, the gas is firstly extracted, after the gas is extracted to a certain degree at an extraction hole, the high frequency oscillator is used to oscillate, and after a certain period of continuous extraction, a pulse aeration module is opened again, a protective gas is impulsively injected into a coal seam, after certain pressure arrives in the borehole in a certain time of pulse aeration, the gas in the borehole is continuously extracted, and thus, the high frequency oscillator is used to promote circulation of the gas, the extraction effects are ensured, the remaining small part of gas is subjected to exchange and circulation by using a pulse aeration mode, and the gas is completely extracted.