To solve the problem that system identification method is difficult to obtain accurate dynamic model for the strain force sensor with complex modal features. The modeling method based on iterative piecewise integration is proposed for establishing the sensor dynamic model. The method transforms sensor dynamic modeling problem into modal parameter identification problem. It uses piecewise integration method to calculate the modal parameters

and adopts iteration method to purposely identify the parameters of each modal of the sensor that has complex modals

accordingly

the dynamic model can be calculated. The modeling results of actual sensor show that the iterative piecewise integration method is more suitable for the dynamic modeling of the sensor that has complex modal features than the system identification method

and can purposely identify the tiny energy modals and dense modals of the sensor; thus

the obtain dynamic model which can accurately reflect rich modal features of sensor;and can provide more accurate basis for the dynamic characteristic analysis and correction of the sensor.