The spatial polarization characteristic of electromagnetic field radiated by linear dipole array and planar-array antenna scanning in different direction was derived and modeled theoretically and mathematical in this paper. The calculation results and simulation analysis show that the polarization properties of phased arrays in various beam positions are diverse, and the polarization state of EM wave will change with the azimuth and elevation of the electrical boresight when the target direction deviates from the antenna boresight direction. The conclusion is of significance to high-precision modeling and simulation for phased array antennas, and is also important for anti-interference by making use of polarization information.