yanchangxianIntroduction：Introduction to the extension: Yanxian County is located in the northwest of Shaanxi Province, east of Yan'an City. The name of the county is named after the Yanhe River flows from the west to the east and flows into the Yellow River. The county is 73 kilometers long from east to west and 55 kilometers wide from north to south. The terrain slopes from northwest to southeast, high in the north and south, and low in the middle. The altitude is 470.6-1383 meters. The early human activities in Yanxian County can be traced back to the Neolithic Age. Established the county in 266 AD. A few degrees of change, to Tang Guangde two years (764), because Yanshui from the county through the long flowing into the Yellow River, began to extend the county, continue to use. The county is a warm temperate arid continental monsoon climate, with four distinct seasons in spring, summer, autumn and winter. The average temperature in winter is 10.4 °C, the total annual sunshine time is 2504.6 hours, the temperature difference between day and night is large, the frost-free period is 170 days, the rainfall is concentrated in July-September, and the annual average precipitation is 564 mm. Yanchang County is rich in land resources. The soil layer mainly composed of loessial soil and black loess soil is deep and the light is sufficient. The temperature difference between day and night is about 20 °C. The precipitation is concentrated in the lush period of crop growth. It is suitable for planting a variety of crops, which is conducive to forestry production. Since the reform and opening up, the county party committee and the government have extended the unity and led the people of the county to adhere to the scientific development concept as the guide, to coordinate the overall situation of urban and rural development, and vigorously implement the development strategy of “project support, town drive, industry enrichment, and industrial strong county”. The county achieved a total production value of 2.96 billion yuan, fixed assets investment of 2.639 billion yuan, local fiscal revenue of 283 million yuan, social consumer goods retail sales of 464 million yuan, urban residents' per capita disposable income of 19,305 yuan, and farmers' per capita net income of 5,378 yuan.