Abstract: To improve the anti-jamming performance of polarization sensitive array(PSA), the performance of alternate polarization sensitive array (APSA) based on the Eigen-space Projection Algorithm is analyzed and compared with the PSA, The influence on signal to interference plus noise ratio (SINR) of polarization match factor and space match factor is discussed. To the further study, the mainlobe anti-jamming performance using the Eigen-space Projection Algorithm based on two kinds of polarization sensitive arrays under the condition that there are errors in the steering vector of the desired signal is analyzed. Theoretical analysis and simulation results show that the mainlobe anti-jamming performance of APSA is robust to errors in the steering vector. The APSA has a low system complexity and is easier to engineering realization.