Mingyue Gorge is a narrow valley, about 4 kilometers long, about 100 meters wide, formed in the historical river, Jialing River broke through the mountains to form a canyon, so the two sides of the stone cliffs magnificent wall. Between the valleys, there is a strange uplift of "anticline"-shaped laminated rocks on one side, which is the "Indo-branch movement" of the late earth 100 million years ago, which made the Devonian, Permian, Triassic and other strata in the original horizontal state of Mingyue Canyon curved upwards and uplifted into anticline. Historically, the ancient plank road of Mingyuexia has been destroyed and repaired several times. It was extensively damaged until the end of Ming and early Qing Dynasty, and the "three wars" in Qing Dynasty was finally abandoned. For more than 300 years, the empty cliff wall only left the pillar holes of the plank road. In 1936, a "C"-shaped groove was excavated above the ancient plank road, commonly known as "tiger mouth", as a passage through Mingyuexia of Sichuan-Shaanxi Highway. At that time, such a "tiger mouth" used hundreds of thousands of forces, starving to death, hundreds of casualties, road construction conditions were very difficult. From 1990 to 1998, it was completely restored with wood and prepared to reproduce the ancient road. Now, perhaps for the safety of tourist passages, the reinforced concrete structure is completely adopted below the road surface, and it seems that there is no antique treatment. It is inevitable that the ancient and steep charm of the ancient road is lost.