This paper proposes a novel method based on target detecting judgment to solve the problem of carrier leakage in Pulse Doppler Radar used for single target detection. The false alarm rate under the assumption of H0 and the detecting performance under the assumption of H1 are compared through simulations. The results show that the novel method can suppress the carrier leakage clearly and effectively without introducing any information of false targets. The novel method has lower false alarm rate and lower wrong detection rate under the assumption of H1, and it can lead to more accurate results of target tracking and recognition. (5 pages)