Using the method of combining theoretical modeling and digital simulation, the error of each chain involved in the measurement and processing of shipborne radar was analyzed, and the error model of each chain such as radar measurement, coordinate transformation, platform attitude positioning and baseline transformation was established. Based on the first-order Taylor expansion, the approximate analytical expression of error chain linearization is given, and the equivalent error model of shipborne radar measurement is established. Theoretical analysis and computer simulation results show that the errors caused by radar azimuth measurement, platform heading and deck heading deformation can be directly added to the azimuth and combined into the azimuth error; at the same time, when the target elevation angle is less than 10 degrees, the influence of deck deformation and platform attitude error on target azimuth measurement can be almost ignored.