Abstract: For solving the problem of the uncertainty about the targets number in the image sequence and initialize the target tracks，this paper researches on the algorithm Track-Before-Detection（TBD） by using a probability-weighted and multi-frame bidirectional correlation method.Firstly，this paper detects the combined frame based the threshold，secondly，through the association of probability of target groups，the authors can gain the initial target location，then by using the two-way correlation of inter-frame goals this paper initializes the track of respective goals.The simulation of results show that the algorithm has a good performance，a small calculation and a good real-time.