Gd2SiO5∶Eu3+ crystal was prepared from an isostatic-pressed-powder rod by optical floating zone method. The structure, composition and optical spectral properties were investigated then. XRD analysis shows crystal grows along the direction as ［001］. And swing curve/Raman analysis shows its crystallization is better than raw powder and rod by. The crystal is not only free of macroscopic defects but also free of microscopic defects. EDS and XPS results show that there is no impurity in the crystal. Furthermore, both Gd3d5/2 and Eu4d5/2 binding energy peaks can be deconvolved into two centers, which are assigned to 7-coordinate and 9-coordinate ones. The absorption of Eu3+-O2- charge transfer band and Gd3+4f-4f electron transition (6D/I/PJ→8S7/2) could be detected in UV-Vis absorption spectrum at the low temperature, and Eg is found to be 5.9 eV with the help of (Ahν)1/2-hν curve. Under ultraviolet excitation, it gives out orange-red fluorescence. Under 254 nm, 277 nm, 365 nm, or 396 nm excitation, the crystal would emit a light centered at 583 nm, 596 nm, 620 nm, 629 nm (related to Eu3+ 5D0→7F0,1,2,3), and the intensity is strongest under 277 nm excitation. Monitored with 583 nm, 596 nm, 620 nm, or 629 nm, the excitation spectrum is similar to each other. The excitation spectrum is in range of 200-500 nm with a broad band centered at 277 nm (corresponding to Eu3+-O2- charge transfer, Gd3+ 8S7/2→6IJ) and peaks at 313 nm (Gd3+ 8S7/2→6PJ), 396 nm (Eu3+ 7F0→5L6), and 466 nm (Eu3+ 7F0→5D3). It could be concluded that a high quality Gd2SiO5∶Eu3+ crystal could be obtained by optical floating zone method.