The invention discloses a double-fin solar heat exchanger, wherein an outer fin is welded on a heat-absorbing surface of an elliptic long shaft made of a metal material at unequal intervals; in winter, the surface temperature of a thermal absorber can be over 80 DEG C; an inner metal fin tube can perform air circulation and also can perform liquid circulation. The double-fin solar heat exchanger has a high heat exchange efficiency, can be used for living heat utilization such as heating, hot air exchange, water heating and the like, can be standardized and generalized for industrial production, can be widely applied to the construction and the reconstruction of a solar heat source, and has an outstanding energy-saving effect.