An efficient target detection algorithm for infrared sequence image with sea-sky background is presented. For the big none-Gaussian noises and the none-linear movement of the target, the algorithm is established mainly on the basis of the Sequential Monte Carlo (SMC) method. The algorithm uses the statistic values of the target's feature image to change the weight of the particles which are produced by Monte Carlo sampling, and the target is detected and tracked based on the control of these weights. The difference image is used as the feature image. The experimental results demonstrate the effectiveness and real-time efficient of the algorithm.