Abstract: With the development of radar towards high integration, high power, multi-function, etc., the antenna structure faces many challenges, such as high integration design, lightweight design, power resistance design and electromagnetic shielding design. Among them, with the increase of power and requirements of multiple functions (detection, jamming, reconnaissance, communication, attack, etc.), the electromagnetic shielding structure design is becoming more and more important. In this paper aiming at the strict electromagnetic shielding effectiveness requirements of a high power radar system with detection and attack functions, according to the structural characteristics of antenna array, the electromagnetic shielding design of antenna is researched in detail from shielding effectiveness distribution, telecommunication basis of shielding design, shielding material selection, electromagnetic shielding design of slot and hole structure, etc. The design strategy for improving the relevant shielding effectiveness of one structure is verified to be effective by engineering tests.