A novel sensor with probe based on acoustic detection is designed.The probe is inserted into the pipe while the acoustic sensor for gas-solid two-phase flow detection is placed outside the pipe.Experiments of single-particle impact and multi-particle impact are carried out and combined with spectrum analyzsis

peak frequency of the acoustic signal is found to be fixed

which is caused by vibration of particles stimulated probe at its natural frequency

and the probe can be approximated regarded as a cantilever beams during the analysis.Pipe experiment shows that peak value at natural frequency has strong relevance with the velocity and mass fraction of the solid phase flow

features of the signal can be used in on-line detection of gas-solid two phase flow in the future.