The invention discloses a fatigue-resistant narrow V-belt and a production method thereof. The fatigue-resistant narrow V-belt comprises a core and wrap. The core includes an extension layer, a strong layer, a buffer layer and a compression layer. A soft toughening layer is arranged between the compression layer and the wrap. The production method includes: mixing, calendering, forming, cutting, wrapping, vulcanizing and cooling. Vulcanizing is performed at the temperature of 160-170 DEG C and under the inner pressure of 0.45-0.55MPa and the outer pressure of 1.0-1.2MPa. Compared with the prior art, the fatigue-resistant narrow V-belt has the advantages that the soft support layer is added in a body of the fatigue-resistant narrow V-belt and has small thickness and large transverse rigidity, and accordingly longitudinal toughness of the body is improved greatly and the transverse rigidity and flexing-aging resistance of the body are improved; bonding force between the soft support layer and the wrap is larger than that between the compression layer and the wrap, the inner pressure of the body can be reduced, the body is more extensible, and operating process is smoother.