A piezoelectric sensor is developed to extract the pulse signal of human body by using the piezoelectric effect produced by some dielectrics. The piezoelectric effect mentioned in other articles refers to the phenomenon that some dielectrics deform (including bending and stretching deformation) under the action of an external force in a certain direction. This kind of deformation is caused by the polarization phenomenon of internal charge, which will generate charge on their surface. Using this phenomenon, the pulse signal of human body can be extracted