In order to improve the accuracy and reliability of grain loss measuring, a scheme of constructing piezocrystal vector sensor arrays was put forward, which realized multi-point parameter real-time measurement. Kinetic model of the grain and straw impacting sensor has been analyzed by the finite element method. According to the dimension of sensitive plate, its model was created via ANSYS to compute the vibration mode and extract resonance frequency of the sensitive element. The location and the quantity of piezocrystal were identified among the vector sensor arrays by analyzing the vibration shape and distribution of dynamic strain about low order modes of sensitive element, which optimized the structure of array. The grain and straw impacting sensor was preceded on test bench. The analysis result has been compared with the measure result that obtained by the dynamic signal analyzer, the conclusion showed that the experimental results was well coincided with theory results. All these are help to devise piezocrystal vector sensor arrays for grain loss of combine and amend its parameters.