The invention discloses a method for changing bandwidth of a fan surface acoustic wave filter. The method is realized through painting a sound absorption glue, and painting of the sound absorption glue is divided into painting of high-frequency part bandwidth sound absorption glue on fingers of an input interdigital transducer and painting of low-frequency part bandwidth sound absorption glue on fingers of an output interdigital transducer; and the method comprises the following specific steps: the high-frequency part bandwidth sound absorption glue is painted downwards from the upper edge of the fingers of the input interdigital transducer, the low-frequency part bandwidth sound absorption glue is used for controlling response of low-frequency part bandwidth and is painted upwards from the lower edge of the fingers, length of the sound absorption glue is controlled by a silk-screen printing plate with adjustable width, the sound absorption glue with fixed length is painted on the surface of a wafer through a silk screen, and thus, needed bandwidth is obtained. According to the invention, bandwidth of the fan surface acoustic wave filter can be changed without changing a finger pattern, and problems of tedious procedures and higher cost caused by redesigning the pattern are solved well.