Abstract: Focusing on the problem of high-precision measurement under the wide dynamic range conditions of large-scale shipborne two-dimensional scanning mechanism-phased array radar, a method is proposed based on the installation of strapdown inertial navigation system (SINS) on phased array antenna to measure its attitude directly, establishes a mathematical model of corresponding beam control, angle measurement, then finished the dynamic calibration based on the least squares algorithm. Through the verification of practical application, the angle measurement accuracy of this method is better than 0. 2 mrad, which realizes high-precision measurement under large-aperture, wide dynamic range phased array radar.