Infrared night vision technique is effective on the security enhancement of sea early warning detection system, but the sea images captured by the infrared night vision viewer usually contain an amount of “background clutter”, it leads to obvious detection performance reduction of sea micro targets. To solve this problem, both active contour model and interpolation filter are combined to propose an accuracy micro target detection algorithm of infrared night vision. Firstly, this algorithm uses global active contour model and local active contour model to search the region of interest, respectively, thus by use of double-layer active contour models, the bad impact of noise and clutter on target detection are eliminated. Then, the interpolation filter with direction variation is proposed to filter the region of interest along the edge, in order to reduce the interference of week edges with the target real edge. Experiments and analysis are carried on the real infrared night vision sea image set, the results show that the proposed method can improve the detection performance of sea micro targets, this algorithm is good for sail on the sea.