Acquiring sequence fingerprint images by sweep fingerprint sensor would cause slide-scar in the vertical direction after image mosaic. In order to remove it, a new quality evaluation and direction judgment based processing method and detection for slide-scar of sliding fingerprint was proposed. When detecting the slide-scar, if the direction of the fingerprint block is in vicinity of 90 degree, vertical lines in the block with good quality are considered to be ridges, while the lines in bad quality block are considered to be scars. For the scar in bad quality block, the average gray value of the block are used to substitute for scar gray; for the scar in good quality block, corresponding treatment is taken depend on whether the scar point is on the ridge or the valley. Experiment had proved the effectiveness of this processing method and detection for slide-scar of sliding fingerprint.