Video leaking signal detection is an important part of TEMPEST, which is the technologies research focus on the investigations and studies of compromising emanations. A novel video leaking signal detection algorithm based on spectral centroid has been developed. Using the property that spectral centroid can accurately identify the signal energy center in frequency domain, the proposed algorithm can detect the display video leaking signal automatically. The uniformity degree of spectral centroid spacing distribution is defined to distinguish the video leaking signal and clutter signal automatically. Furthermore, the ant-jamming and ant-noise performance of the developed algorithm is analyzed in a practical attack scenario.