Liangdang County, subordinate to Longnan City, Gansu Province, is located in the southeast of Gansu Province and the northeast of Longnan City. By the end of 2019, Liangdang had jurisdiction over 6 towns and 6 townships, 2 workstations and 118 administrative villages, with a total area of 1408 square kilometers. According to the data of the seventh population census, as of 0:00 on November 1, 2020, the permanent population of Liangdang County is 39709.

In ancient times, Liangdang was called Gudao and Gudao. In the reign of King Huiwen of the Qin Dynasty, Gudao County was established, and Liangdang County, Gudao County, was established in the Northern Wei Dynasty. It was named after the Liangdang River in the territory. After 1985, it was under the jurisdiction of Longnan District and Longnan City. Located in the Qinling Mountains at the junction of Shaanxi, Gansu and Sichuan, it is known as "the shield of Qinlong and the silent throat of Bashu". Its altitude is between 773-2738 meters, belonging to the continental monsoon climate of warm temperate zone, with abundant light and heat, abundant rainfall and significant differences. There are rare animals such as Qinling takin, clouded leopard and forest musk deer in the territory, and there is Xiaolongshan National Nature Reserve in Gansu Province. Natural resources include hydropower resources, biological resources, mineral resources, etc. In 2015, Liangdang County achieved a gross output value of 601 million. It is "China's Deep Breathing Town", "National Civilized County", "National Green Model County", "National Ecological Garden County", and "China's Green Famous County". Its famous and famous specialties include wolf tooth honey, seven-li incense, ginkgo, black fungus, etc. There are tourist attractions such as the Memorial Hall of Two Soldiers, Yunping Sanxia Natural Scenic Spot, Lingguan Gorge Zhangguo Laodengzhen Cave, Heihe Nature Reserve, etc. On September 25, 2018, it was awarded the honorary title of "2018 Comprehensive Demonstration County of E-commerce in Rural Areas" by the Ministry of Commerce. In October 2018, the Gansu Provincial Government issued a notice officially approving Liangdang County to withdraw from the poverty county sequence. In December 2018, it won the title of the second batch of national ecological civilization construction demonstration cities and counties.

In 2020, the gross domestic product of Liangdang County will reach 1.11 billion yuan, an increase of 1.6%, the total retail sales of consumer goods will reach 134.8 million yuan, and the investment in fixed assets will reach 343 million yuan.