A light source module and a wavelength conversion module are provided. The light source module includes a first light emitting device, a reflection unit, a wavelength conversion unit, a second light emitting device and a light combination unit. The first light emitting device emits an exciting beam. The reflection unit is disposed on a transmission path of the exciting beam. The wavelength conversion unit is disposed on the reflection unit and located on the transmission path of the exciting beam. The exciting beam is obliquely incident into the wavelength conversion unit along an optical axis of the first light emitting device, and the wavelength conversion unit converts the exciting beam into a first color beam. The second light emitting device emits a second color beam. The light combination unit is disposed on transmission paths of the first color beam and the second color beam.