A projection apparatus comprising a first light source assembly (100, 200), wherein the first light source assembly (100, 200) comprises: a first excitation light source (110, 210), configured to provide a first excitation beam, a second excitation light source (120, 220), configured to provide a second excitation beam, wherein the first excitation beam and the second excitation beam have the same color, a first dichroic element (130, 230), wherein the second excitation beam is transmitted toward the first excitation light source (110, 210) via the first dichroic element (130, 230), a first wavelength conversion element (140, 240), disposed between the first excitation light source (110, 210) and the first dichroic element (130, 230), wherein the first wavelength conversion element (140, 240) is configured to convert the first excitation beam and the second excitation beam into a first wavelength conversion beam and transmit the first wavelength conversion beam toward the first dichroic element (130, 230), a first collimating element (150, 250), disposed between the first wavelength conversion element (140, 240) and the first dichroic element (130, 230), and a second collimating element (160, 260), disposed between the second excitation light source (120, 220) and the first dichroic element (130, 230), characterized in that: the optical distance of the second excitation beam from the second excitation light source (120, 220) to the first dichroic element (130, 230) is equal to the optical distance of the first wavelength conversion beam from the first wavelength conversion element (140, 240) to the first dichroic element (130, 230), the first collimating element (150, 250) and the second collimating element (160, 260) have the same configuration, and an area size of a light-exiting surface of the second excitation light source (120, 220) is the same as an area size of a light-exiting surface of the wavelength conversion element (140, 240), respectively. a first excitation light source (110, 210), configured to provide a first excitation beam, a second excitation light source (120, 220), configured to provide a second excitation beam, wherein the first excitation beam and the second excitation beam have the same color, a first dichroic element (130, 230), wherein the second excitation beam is transmitted toward the first excitation light source (110, 210) via the first dichroic element (130, 230), a first wavelength conversion element (140, 240), disposed between the first excitation light source (110, 210) and the first dichroic element (130, 230), wherein the first wavelength conversion element (140, 240) is configured to convert the first excitation beam and the second excitation beam into a first wavelength conversion beam and transmit the first wavelength conversion beam toward the first dichroic element (130, 230), a first collimating element (150, 250), disposed between the first wavelength conversion element (140, 240) and the first dichroic element (130, 230), and a second collimating element (160, 260), disposed between the second excitation light source (120, 220) and the first dichroic element (130, 230), characterized in that: the optical distance of the second excitation beam from the second excitation light source (120, 220) to the first dichroic element (130, 230) is equal to the optical distance of the first wavelength conversion beam from the first wavelength conversion element (140, 240) to the first dichroic element (130, 230), the first collimating element (150, 250) and the second collimating element (160, 260) have the same configuration, and an area size of a light-exiting surface of the second excitation light source (120, 220) is the same as an area size of a light-exiting surface of the wavelength conversion element (140, 240), respectively. the optical distance of the second excitation beam from the second excitation light source (120, 220) to the first dichroic element (130, 230) is equal to the optical distance of the first wavelength conversion beam from the first wavelength conversion element (140, 240) to the first dichroic element (130, 230), the first collimating element (150, 250) and the second collimating element (160, 260) have the same configuration, and an area size of a light-exiting surface of the second excitation light source (120, 220) is the same as an area size of a light-exiting surface of the wavelength conversion element (140, 240), respectively.