The invention discloses a sounding device and an installation method thereof. The sounding device comprises a casing, a cover plate, an accommodation space, a single sounder unit, a sound absorbing material and an isolation net, wherein the cover plate covers the casing, the accommodation space is formed by the casing and the cover plate, the single sounder unit and the sound absorbing material are accommodated in the accommodation space, and the isolation net is accommodated in the accommodation space. The isolation net divides the accommodation space into a front cavity and a rear cavity ventilated with the front cavity, the single sounder unit is accommodated in the front cavity, and the sound absorbing material is accommodated in the rear cavity. The cover plate comprises a front cover plate body which covers the front cavity and a rear cover plate body which covers the rear cavity. The installation method comprises the following steps that the single sounder body is accommodated in the front cavity; the front cover plate body covers the front cavity body; the isolation net is placed between the front cavity and the rear cavity; the sound absorbing material is mounted in the rear cavity; the rear cover plate body covers the rear cavity; and the front and rear cover plate bodies are sealed with the casing to form the sounding device. Thus, assembling is convenient.