Molybdenum trioxide (MoO3) is an interesting material for smart windows, electrodes for batteries, and gas sensors. So far, it is known that the growth of large single crystal of MoO3 is elusive because of the rapid changing of activation energy at 650 degrees C. Small MoO3 crystals can be made by sublimation. In this study, we successfully grew large MoO3 single crystals through the modified vertical Bridgman method, which can prevent the sublimation of MoO3. Similar structural and optical properties were measured like those of nano/micro-crystalline MoO3. This study can provide evidence to contribute to the creation of large single crystals, which have a lower sublimation temperature than melting temperature.