The invention discloses a defect detection system of a component, which comprises a component to be detected, a platform carrying the component to be detected, a power supply unit and a light source device, wherein the light source device is controlled by the power supply unit to supply detection light to the component to be detected for defect detection; the light source device comprises a cathode structure, an anode structure, a fluorescent layer and a low-pressure gas layer; the fluorescent layer is positioned between the cathode structure and the anode structure; and the low-pressure gas layer is filled between the cathode structure and the anode structure, has the function of inducing the cathode structure to uniformly emit electrons, wherein the air pressure of the low-pressure gas layer is at the range of 0.1-10-3 torr, and the low-pressure gas layer is provided with an electron mean free path where at least enough number of electrons are allowed to directly collide with the fluorescent layer at operating voltage.