A projection device includes a light source module and a light splitter module. The light source module includes a first light source, a second light source, a reflection module and a polarizing module. The first light source emits a first light beam with a first polarization direction. The second light source emits a second light beam with a second polarization direction. The reflection module is disposed corresponding to the first light source along the first axis, and is used to reflect the first light beam to a second axis. The polarization module is disposed corresponding to the second light source along the first axis and corresponding to the reflection module along the second axis. The polarization module is used to direct the first light beam to pass through the polarization module along the second axis and reflect the second light beam to the second axis through the light splitter module.