In the linear accelerometer dynamic calibration of double centrifuge, three-parameter cosine algorithm runs through the entire test of the amplitude frequency characteristic, phase frequency characteristic and amplitude linearity. This paper describes the concept and the derivation process of the three-parameter cosine algorithm, its practical application in computational process of dynamic calibration of double centrifuge linear accelerometer, and the implementation of three-parameter cosine algorithm. And the paper introduces the selection method of collection points in the amplitude frequency characteristic and phase frequency characteristics, so as to reduce the impact of different selection methods on data fitting accuracy. Taking a linear accelerometer as an example, double centrifuge were used for dynamic calibration, and the accelerometer data are collected and calculated to give the fitting curve and the result, which verifies the feasibility of the three-parameter cosine algorithm program.