A light source device (100, 200, 300, 400, 500), comprising: an exciting light source (10, 20, 30, 40, 50) for generating exciting light; a light condensing device (13, 23, 33, 44, 54); and a fluorescent cavity (14, 25, 37, 46, 57), wherein the fluorescent cavity comprises a chamber (141, 261, 371, 461, 571) and a fluorescent layer (145, 265, 375, 465, 575), the chamber (141, 261, 371, 461, 571) having a light window (142, 262, 372, 462, 572) allowing light to enter and exit and a bottom wall (143, 263, 373, 463, 573) opposite to the light window (142, 262, 372, 462, 572), and the fluorescent layer (145, 265, 375, 465, 575) being provided on a surface of the bottom wall (143, 263, 373, 463, 573); and wherein the exciting light is converged by the light condensing device (13, 23, 33, 44, 54), then incident to a surface of the fluorescent layer (145, 265, 375, 465, 575) from the light window (142, 262, 372, 462, 572) to form a light spot which excites the fluorescent layer (145, 265, 375, 465, 575) to generate excited light, wherein an area of the light window (142, 262, 372, 462, 572) is smaller than an area of the light spot, and the excited light is emitted from the light window (142, 262, 372, 462, 572), characterized in that light source device (100, 200, 300, 400, 500) further comprises: a light homogenizing element (11, 21, 31, 41, 51), wherein the exciting light emitted from the exciting light source (10, 20, 30, 40, 50) is homogenized by the light homogenizing element (11, 21, 31, 41, 51), and a light splitting element (12, 22, 32, 42, 52), wherein the light splitting element (12, 22, 32, 42, 52) receives the exciting light homogenized by the light homogenizing element (11, 21, 31, 41, 51), and is configured to reflect a part of the exciting light and transmit the excited light, wherein the exciting light source (10, 20, 30, 40, 50) and the chamber (141, 261, 371, 461, 571) are disposed in a same side of the light splitting element (12, 22, 32, 42, 52). an exciting light source (10, 20, 30, 40, 50) for generating exciting light; a light condensing device (13, 23, 33, 44, 54); and a fluorescent cavity (14, 25, 37, 46, 57), wherein the fluorescent cavity comprises a chamber (141, 261, 371, 461, 571) and a fluorescent layer (145, 265, 375, 465, 575), the chamber (141, 261, 371, 461, 571) having a light window (142, 262, 372, 462, 572) allowing light to enter and exit and a bottom wall (143, 263, 373, 463, 573) opposite to the light window (142, 262, 372, 462, 572), and the fluorescent layer (145, 265, 375, 465, 575) being provided on a surface of the bottom wall (143, 263, 373, 463, 573); and wherein the exciting light is converged by the light condensing device (13, 23, 33, 44, 54), then incident to a surface of the fluorescent layer (145, 265, 375, 465, 575) from the light window (142, 262, 372, 462, 572) to form a light spot which excites the fluorescent layer (145, 265, 375, 465, 575) to generate excited light, wherein an area of the light window (142, 262, 372, 462, 572) is smaller than an area of the light spot, and the excited light is emitted from the light window (142, 262, 372, 462, 572), characterized in that light source device (100, 200, 300, 400, 500) further comprises: a light homogenizing element (11, 21, 31, 41, 51), wherein the exciting light emitted from the exciting light source (10, 20, 30, 40, 50) is homogenized by the light homogenizing element (11, 21, 31, 41, 51), and a light splitting element (12, 22, 32, 42, 52), wherein the light splitting element (12, 22, 32, 42, 52) receives the exciting light homogenized by the light homogenizing element (11, 21, 31, 41, 51), and is configured to reflect a part of the exciting light and transmit the excited light, wherein the exciting light source (10, 20, 30, 40, 50) and the chamber (141, 261, 371, 461, 571) are disposed in a same side of the light splitting element (12, 22, 32, 42, 52). a light homogenizing element (11, 21, 31, 41, 51), wherein the exciting light emitted from the exciting light source (10, 20, 30, 40, 50) is homogenized by the light homogenizing element (11, 21, 31, 41, 51), and a light splitting element (12, 22, 32, 42, 52), wherein the light splitting element (12, 22, 32, 42, 52) receives the exciting light homogenized by the light homogenizing element (11, 21, 31, 41, 51), and is configured to reflect a part of the exciting light and transmit the excited light, wherein the exciting light source (10, 20, 30, 40, 50) and the chamber (141, 261, 371, 461, 571) are disposed in a same side of the light splitting element (12, 22, 32, 42, 52).