A color wheel apparatus, comprising a wavelength conversion layer , a sealed housing , a cover body , a heat exchanger and a color wheel module , wherein: the wavelength conversion layer is configured to be illuminated by excitation light and to generate excited light; the sealed housing is configured to form a sealed cavity and to accommodate the wavelength conversion layer , the cover body , the heat exchanger and the color wheel module in the sealed cavity; the cover body has an outer edge fixedly connected to the sealed housing , wherein the cover body together with the sealed housing form a color wheel cavity for accommodating the wavelength conversion layer and the color wheel module , wherein a first opening is provided at a central portion of the cover body, one or more second openings are provided at an edge of the cover body, the first opening forms an air inlet of the color wheel cavity , and the second openings form an air outlet of the color wheel cavity ; the heat exchanger is located outside the color wheel cavity , wherein the heat exchanger comprises a heat exchange inlet and a heat exchange outlet ; and the color wheel module is disposed in the color wheel cavity , supporting the wavelength conversion layer , and configured to provide power for enabling an air flow to enter through the air inlet of the color wheel cavity and leave through the air outlet , so as to form a circulation air duct in which the air flow sequentially passes through the air inlet of the color wheel cavity , the color wheel module , the air outlet of the color wheel cavity , the heat exchange inlet , and the heat exchange outlet and then returns to the air inlet . the wavelength conversion layer is configured to be illuminated by excitation light and to generate excited light; the sealed housing is configured to form a sealed cavity and to accommodate the wavelength conversion layer , the cover body , the heat exchanger and the color wheel module in the sealed cavity; the cover body has an outer edge fixedly connected to the sealed housing , wherein the cover body together with the sealed housing form a color wheel cavity for accommodating the wavelength conversion layer and the color wheel module , wherein a first opening is provided at a central portion of the cover body, one or more second openings are provided at an edge of the cover body, the first opening forms an air inlet of the color wheel cavity , and the second openings form an air outlet of the color wheel cavity ; the heat exchanger is located outside the color wheel cavity , wherein the heat exchanger comprises a heat exchange inlet and a heat exchange outlet ; and the color wheel module is disposed in the color wheel cavity , supporting the wavelength conversion layer , and configured to provide power for enabling an air flow to enter through the air inlet of the color wheel cavity and leave through the air outlet , so as to form a circulation air duct in which the air flow sequentially passes through the air inlet of the color wheel cavity , the color wheel module , the air outlet of the color wheel cavity , the heat exchange inlet , and the heat exchange outlet and then returns to the air inlet . <EOS>