A piezoelectric thrust-measuring platform with high natural frequency is developed for measuring the pulsed thrust generated by attitude-control rocket engines. It consists of two shear mode piezoelectric quartz crystal sensors and an integral shell. The sensors are inserted into the grooves of the elastic rings with an interference fit. Shell stiffness is calculated by energy method (EM) and finite element method (FEM). The shell is optimized for obtaining a good compromise between the sensitivity and frequency response. The stiffness and natural frequency after optimization are verified by experiments. The results show that the stiffness calculated by FEM is more accurate than that calculated by EM. The sensitivity of the thrust-measuring platform is increased by 13.6% compared with before optimization. The natural frequency of the thrust measurement system is 1245 Hz.