The invention provides a double-field-of-view long-wave infrared optics passive athermalization optical system. The double-field-of-view long-wave infrared optics passive athermalization optical system is an athermal double-field-of-view optical system which is high in utilization rate of lenses, has double fields of view, can automatically adapt to environmental temperature changes, and can achieve athermalization and achromatism. According to the technical scheme, a front fixing set is composed of a convex negative lens (7) which is arranged between a positive lens (8) and a zoom lens negative lens (6), and the positive lens; a rear fixing set is composed of a lens (5), a negative lens (4) close to the lens (5), a concave and convex surface lens (2) and a convex lens (3) close to the convex surface of the concave and convex surface lens (2). The zoom lens negative lens moves back and forth in the direction of an optical axis by using a motor as a driving source, the focal length of the zoom lens negative lens changes from 50mm to 150mm in a switching mode, and two-gear double-field-of-view zooming is achieved; when in a Long focal length state, an aperture diaphragm of the optical system is located on a biconvex lens; when in a short focal length state, the aperture diaphragm of the optical system is located on the positive lens; an integral imaging system is formed by the zoom lens negative lens, the front fixing set and the rear fixing set together.