The invention provides a reversing valve for reversing a fluid flow, comprising a valve housing defining a cylindrical chamber, at least four passage outlets being formed in the valve housing and opening into the cylindrical chamber, and further comprising a valve core being received rotatably and hermetically within the cylindrical chamber of the valve housing, at least two passages being defined in the valve core, wherein the passage outlets and the passages are arranged such that the reversing valve can reverse the liquid flow once every time that the valve core rotates through 90°. The invention also provides a high frequency oscillation airflow generator. According to the invention, the reversing frequency of the gas flow and thus the efficiency of the high frequency oscillation airflow generator are improved.
