## 2 Literature Review  
### Impact of Tertiary Industry Development on the Logistics Express Industry  
[PERSON] et al. [4] noted that since China acceded to the World Trade Organization at the beginning of the 21 st century, the country has seen a significant increase in opportunities to engage in international export trade, gradually establishing itself as a major exporting nation. This rapid economic development has led to substantial changes in the industrial structure, with the share of the tertiary sector in China's output rising from 36.2 percent in 1998 to 44.6 percent in 2012. As China enters a new phase of economic development, the government has emphasized the importance of achieving high-quality economic growth through the optimization of its industrial structure.  
[PERSON] [5]'s research argues, as the proportion of the tertiary industry within the national economy continues to rise, its internal structure is undergoing significant changes. The shares of both living services and production services have increased alongside a growing number of modern service industries that have been enhanced through the application of advanced industrial information technologies, notably exemplified by logistics and distribution services. Many regions are prioritizing the logistics industry as a key sector in their plans for developing the tertiary industry. However, the advancement of the modern logistics industry is inextricably linked to the support of transportation networks, professional infrastructure, and effective management conditions. Therefore, Regional governments must avoid neglecting the foundational environmental conditions necessary for the growth of the logistics sector. Additionally, as a service-oriented industry, the demand for logistics services directly influences the trajectory of its development. [PERSON] et al. [6] analyzed the characteristics of the spatial distribution of industries in China and concluded that the long-term distribution of employment in tertiary industry shows a concentration trend toward large cities. [PERSON] et al. [7] discussed and studied the spatial distribution characteristics of the tertiary industry in the Pearl River Delta city cluster by using the Dagum Gini coefficient, kernel density estimation, local spatial auto-regression, etc. The results of the study showed that the tertiary industry agglomeration effect was most obvious in Guangzhou and Shenzhen, with a higher degree of agglomeration of consumptive and productive tertiary industries. The above study shows that the development trend of tertiary industry in China's large and medium-sized cities is not balanced, and the development of logistics can strengthen the flow of resources and links between city networks. It is indispensable to pay attention to the development of the logistics industry in the future development of tertiary industry in China.  
In general, China's tertiary industry and the logistics and express delivery sector exhibit a complementary relationship. The advancement of the tertiary industry facilitates the transformation and upgrading of the logistics and express delivery sector by providing essential foundational elements, such as transport infrastructure, regional logistics demand, and a skilled workforce. Conversely, the growth of the logistics and express delivery industry lays the groundwork for the structural optimization of tertiary industry, thereby enhancing its efficiency and responsiveness to market demands.