Effects of different pretreatments and observation modes on embryo characteristics,especially the embryo sac,were studied using Malus hupehensis and the aneuploid plant from the hybridization of Malus hupehensis and Malus.baccata as experimental materials.Result showed that the clearest images of embryo characteristics could be obtained by using 4% sucrose-eosin dyestuff to stain the whole ovule,then washing the materials sufficiently and choosing LSCM 1024×1024 image resolution to observe.