The invention discloses a powder material sound velocity measurement method. The method is characterized by comprising the following steps: enabling a sound source to couple with an sound bearing medium under a state that the sound bearing medium is not contacted with a to-be-measured powder material, controlling the sound source to emit a sound wave signal to the sound bearing medium, and receiving an echo amplitude Pa when an echo arrives the sound source after the sound wave is reflected by the sound bearing medium and an air interface; enabling the sound source to couple with the sound bearing medium under the state that the sound bearing medium is contacted with the to-be-measured powder material, controlling the sound source to emit the sound wave signal to the sound bearing medium,and receiving the econ amplitude P1 when the echo arrives the sound source after the sound wave signal is reflected by the sound bearing medium and a powder interface; and computing the sound pressurereflective coefficients of the sound medium and a powder interface through the echo amplitude Pa and the echo amplitude P1; and computing the characteristic impedance of the to-be-measured powder material through the sound pressure reflective coefficient, and computing the sound speed of the to-be-measured powder material according to the characteristic impedance. The sound speed measurement method disclosed by the invention can perform sound speed measurement on various working conditions, and has the advantages of being fast in speed and strong in generality.