Abstract: Orthoimage has relief displacements in image edge and the area with buildings or trees. And displacements display differently on different orthoimages. An ideal seam-line should steer clear of high-displacement-area. This paper proposes an approach of advanced Minimizing Local Maximum in searching seam-line on differential image of overlapped region between mosaicked orthoimages. The experimental results have shown that this method is self-adaptive, and is able to select a seam-line which can steers clear of high-displacement-area, to achieve seamless mosaic.