The invention relates to the technical field of sound box parts, in particular to an anti-distortion high-tone-quality sound box diaphragm. The diaphragm comprises a diaphragm body, a composition mechanism is arranged in the diaphragm body, a suppression mechanism and an expansion mechanism are arranged on the diaphragm body, and an abutting mechanism is connected between the expansion mechanism and the suppression mechanism; through the arrangement of the composition mechanism, various materials can be combined together to be pressed into the vibrating diaphragm, the bucket effect is avoided by utilizing the complementary advantages of the various materials, and the sounding effect of the loudspeaker box under high and low frequencies is improved; the damping effect can be provided for the vibrating diaphragm through the suppression mechanism, the resonance of the vibrating diaphragm is suppressed, and the tone quality is improved, and the expansion mechanism drives the suppression mechanism through the abutting mechanism, so that the damping strength of the suppression mechanism can be adjusted, the vibrating diaphragm can be adjusted more conveniently, and the vibrating diaphragm is more excellent in the use process.