A light source system, comprising: a wavelength conversion layer (102, 202) used for receiving exciting light (L3) and generating excited light (L2); a transparent thermal conduction substrate (104, 204) used for supporting the wavelength conversion layer (102, 202), and an excitation light source which emits the exciting light (L3) from a side of the wavelength conversion layer (102, 202) to the wavelength conversion layer (102, 202); and a red light source which emits red light (L1) from a side of the transparent thermal conduction substrate (104, 204) to the wavelength conversion layer (102, 202). The light source system can effectively solve the problem of insufficient red light in fluorescent powder excitation technology.