A method of detecting particles on a panel comprises the following steps: illuminating, using a light source module (10), a panel to be detected (40), and generating an illumination field; adjusting a halfwidth of the illumination field; adjusting luminous intensity at the center of the illumination field and luminous intensity at the edge of the halfwidth of the illumination field; adjusting light intensity and a position of the light source, and a position of a detector (20); and acquiring, by the detector (20), a panel foreign object signal. The method is utilized to significantly reduce crosstalk of particle images and a panel lower surface pattern, increasing a signal-to-noise ratio, thereby increasing accuracy of detecting a foreign object at a panel.
