The invention discloses an engine air valve continuously variable driving mechanism, which comprises an air valve top and a camshaft with a cam; also comprises the following components: a control shaft mounted in parallel with the camshaft; a sun gear fixed on the control shaft; an output cam mounted on the control shaft in a rotatable way, while connected with the air valve top in an operatable way; a rocker arm mounted on the control shaft in a rotatable way; a roller mounted on the rocker arm in a rotatable way, while contacting the cam on the camshaft; a planetary gear mounted on the rocker arm in a rotatable way, while geared with the sun gear; and a crank fixed with the planetary gear, while contacting the output cam. Adopting the air valve driving mechanism in the invention can cancel engine throttle, thereby reduce pumping loss and fuel consumption, and optimize the torque output under all working conditions. The invention achieves the advantages of simple structure, small weight and size of components, large control range and convenient regulation; and has less change to the engine cylinder cover.