Abstract: According to the requirement of high isolation of millimeter wave radar, a millimeter wave dual polarization antenna was designed by using metal column load and cross slot. The antenna has dual polarization, broadband and high isolation performance. The broadband characteristic of the antenna is determined by the size of radiation patch and parasitic patch. The high isolation characteristic is due to two kinds of polarization layered feeding. The metal column is loaded next to the cross gap, so that the gap is easier to couple energy. According to the simulation analysis results, the bandwidth of the antenna is 24.0 - 28.5 GHz, the relative bandwidth is 17.1%, the isolation in the frequency band is more than 47 dB, and the cross polarization ratio is greater than 22 dB. It realizes the characteristics of broadband, high isolation and low cross polarization, and is suitable for millimeter wave dual polarization radar.