A correlation algorithm studied in this paper is mainly applied to terminal air to ground missile guidance. Now the practical application of laser、GPS、SAR terminal missile guidance in China is not mature, and conventional E.O、infrared missile guidance is still of great potential. Therefore correlation algorithm based on video signal is of great study value. Two kinds of correlation algorithm studied in this paper are multiple point correlation (MPC) and region template correlation (RTC). MPC algorithm has high tracking sensitivity and good locating accuracy. Its hardware can be simply constructed so that it has good real-time performance. RTC algorithm not only considers the intensity feature of target region, but also considers multi-layer location feature and area feature. So it is a rather robust algorithm. To deal with the problems existed in practical application, these two kinds of algorithm are further explored and some efficient measure is put forward. Finally, these two kinds of algorithm have been combined in this paper, first: acquiring a tracking point through raw and fine image registration; second: a kind of energy function proposed to measure template updating. Many experiment results show that under complex background and foreground, two kinds of algorithm improved in the paper can track target more steadily. A hybrid algorithm has further upgraded target tracking probability and precision. Now, some correlation tracking technology has already been applied to practical engineering project.