A novel rapid prototyping technology for glass-alumina functionally gradient materials (G-A FGMs) based on the quick solidification of wax was proposed. The feature of the technology came from its layer-by-layer fabrication of the wax-glass/alumina composite layer. With the help of orthogonal experiment method, the influence of different parameters (sintering temperature, component ratio (the glass and the alumina), and number of layers) on the flexural strength of FGMs was discussed. Optimum conditions obtained from the above experiments were applied to prepare the G-A FGM with three layers. The G-A FGM was analyzed in detail, by observing it under an environmental scanning electron microscope (ESEM) coupled with an X-ray energy dispersive spectrometer (X-EDS). The results of orthogonal experiment show that number of layers is the principal parameter to the flexural strength of FGMs, component ratio is the secondary factor, and sintering temperature may be not an important factor. The special microstructure appears in the cross section of the G-A FGM, observed by ESEM. It is from the X-EDS graph concluded that alumina and glass probably react to form the special microstructure with part removal of wax.