The invention relates to an embedded type optical system of an operating illuminating lamp. The embedded type optical system of the operating illuminating lamp adopts a micro-curved-surface array reflecting mirror which is a curved surface formed by a micro-reflecting-surface array. On the premise of guaranteeing that a deck is not higher than 15 mm, a high-luminance illuminating effect is provided for a working area, so that light intensity of a main light beam is not smaller than 2500 cd within a horizontal divergence angle of (-)5 degrees to (+)5 degrees, and a perpendicular divergence angle of 0 degrees to (+)9 degrees.