Abstract: High-resolution images achieved by unmanned aerial vehicle(UAV) are superior in many aspects such as low cost,convenience and so on.However,the coverage of the images obtained by low altitude flight is usually small,and a mosaic should be made to increase the visual field.A mosaicking method based on the seam line is presented,and some improvements are made to improve the effect of the mosaic.Some experiments are made to test the improved method,and the results are satisfactory.