supporting frame 21 c is in the center and the supporting frame 23 c is symmetrically on the both sides apply adhesive agent on the adhesive cambered surface of the supporting frame 21 c and 23 c and imbed the quartz wafer 22 c 1 and 22 c 2 in the cambered surface the two flexible hinges of the supporting frame have a thickness of 0 2 mm 0 7 mm and are made of 1cr18ni9ti the lead in wires of the two piezoelectric quartz wafers are connected with the excitation circuit respectively the sensitive direction of the accelerometer is the center connecting direction of the two piezoelectric quartz wafers when acceleration is inputted the forces exerted on the two piezoelectric quartz wafer change one wafer increases in pressure and the other increases in tension so that one wafer increases its frequency and the other decreases its frequency a digital signal proportional to the acceleration can be obtained through the differential frequency this structure is suitable to detect high acceleration the sensitive element 3 comprises an axial shock absorber and a transverse retaining unit for protecting the two round piezoelectric quartz wafers 22 from overload the axial shock absorber comprises a sensitive block 20 and a shock pad 31 between the.