In order to improve the bandwidth and ability to resist electromagnetic interference of phased array antenna, we use the real-time delay technology of optical fiber. By using phase control principle of optically controlled phased array, we deduce the relation formula of time delay and phase control. Based on multiple optical carriers and optical switch delay technology, we analyze design method of optical fiber time delay system and give the results of the experimental test. From the results, we find that the system can improve ability of phased array antenna about phase control and resisting electromagnetic interference in broadband condition.