Dual-energy　digital　mammography　(DEDM)　can　suppress　the　contrast　between　adipose　and　glandular　tissues　and　generate　dual-energy　(DE)　calcification　signals.　DE　calcification　signals　are　always　influenced　by　many　factors.　Image　noise　is　one　of　these　factors.　In　this　paper,　the　sensitivity　of　DE　calcification　signal　to　image　noise　was　analyzed　based　on　DEDM　physical　model.　Image　noise　levels　of　two　different　commercially　available　digital　mammography　systems,　GE　Senographe　Essential　system　and　GE　Senographe　DS　system,　were　measured.　The　mean　noise　was　about　1.04%　for　Senographe　Essential　system,　1.42%　for　Senographe　DS　system　at　28kVp/50mAs;　and　was　0.47%　for　Senographe　Essential　system,　0.79%　for　Senographe　DS　system　at　48kVp/12.5mAs.　Evaluations　were　performed　by　comparing　RMS　(Root-Mean-Square)　of　calcification　signal　fluctuations　in　background　regions　and　CNR　(Contrast-Noise-Ratio)　of　calcification　signals　in　clusters　when　these　two　digital　mammography　systems　were　used.　The　results　showed　that　image　noise　had　a　serious　impact　on　DEDM　calcification　signals.　If　GE　Senographe　Essential　system　was　used,　calcification　signal　fluctuations　were　200　similar　to　300　mu　m,　and　when　calcification　size　is　greater　than　300　mu　m,　the　probability　of　acquiring　CNR　＞=　3　is　over　50%.　If　noise　reduction　techniques　are　used,　the　calcification　threshold　size　of　CNR　＞=　3　can　be　lower.