X-ray scatter leads to erroneous calculations of dual-energy digital mammography (DEDM). The existing methods for scatter correction in DEDM are using anti-scatter grids or the pinhole-array interpolation method which is complicated and impractical. In this paper, a scatter correction algorithm for DEDM is developed based on the knowledge that scatter radiation in mammograms varies slowly and most pixels in mammograms are non-microcalcification pixels. The proposed algorithm only uses the information of low-energy (LE) and high-energy (HE) images. And it doesn't need anti-scatter grids, lead sheet and extra exposures. Our results show that the proposed scatter correction algorithm is effective. When using the simple least-squares fit and linear interpolation, the scatter to primary ratio (SPR) can be decreased from ~33.4% to ~2.8% for LE image and from ~26.2% to ~0.8% for HE image. Applying scatter correction to LE and HE images, the resultant background signal in the DE (dual-energy) calcification image an be reduced significantly.