The present invention discloses an optical system, an optical interference system, and an optical method for synchronously measuring an absolute addressing distance and a yaw angle, wherein the optical system comprises a focusing lens, a birefringent spectroscopic element, and a spectroscopic element. The birefringent spectroscopic element is used to spectrally beam the focused lens to form the polarized light and the second polar light which are orthogonal to each other. And the second polarized light and the second polarized light are reflected by the spectroscopic element to form a reference light and a second reference light, the partial polarized light and the second partial Aurora penetrating the spectroscopic element onto the object to reflect the formation of the incident light and the second object light, the light and the second object light entering the spectroscopic element so as to interfere with the reference light and the second reference light The interference light and the second interference light are combined with the birefringent optical element to form a combined light beam which does not interfere with each other.