Abstract: The application of dual-polarization microstrip array antenna in mono-pulse radar system is introduced. The radar system may achieve polarization diversity and multi-polarization angle error extraction abilities with this design. A mono-pulse antenna array is accomplished with two dual-polarization sub-arrays. Amplitude comparing angle error extraction method and polarization synthesize technique are absorbed to obtain sum and difference beam patterns and angle error curves in linear, circular and ellipse polarization waves. A low cost two dimensional mono-pulse antenna array is also represented. Both azimuth and pitch angle error extraction methods are introduced. The results show the feasibility of dual-polarizaiton mono-pulse antenna based on stacked structure.