The invention provides a method for controlling noises of a leading edge slat of an airplane. The method comprises the following steps: mounting a first piezoelectric sensor on the inner surface of a slat groove of the leading edge slat, so as to absorb mechanical energy of airflow vortex impact by using a piezoelectric effect and convert the mechanical energy into electric energy; and providing a piezoelectric shunt circuit module to be electrically connected with the first piezoelectric sensor so as to dissipate the electric energy in a manner of heat. The invention further provides an active noise reduction method for the leading edge slat of the airplane and an active-passive integrated noise reduction method. According to the method provided by the invention, the aerodynamic noises of the slat can be controlled effectively under the premise that the design of a conventional high-lift device is not changed greatly, and influences on the aerodynamic performance of the high-lift device and the safety of the airplane are not generated.