Scenic symbiosis, which is of great research significance, is an important way to achieve high-quality coordinated development of regional tourism. Based on the symbiosis theory, this paper defines the symbiosis intensity of scenic spots and establishes a calculation scheme. On the one hand, it measures the spatiotemporal evolution characteristics of symbiosis intensity of 281 scenic spots in Hunan Province from September 2018 to December 2021. On the other hand, it uses a multiple linear regression model to quantitatively explore its influence mechanism. The results indicate that: (1) From September 2018 to December 2021, the tourism demand in Hunan Province presented fluctuations due to the impact of the COVID-19 pandemic, which can be divided into three stages: “slight increase before the COVID-19 pandemic”, “rapid decline during the COVID-19 pandemic”, and “slow recovery after the COVID-19 pandemic”; (2) The symbiosis intensity of scenic spots is mainly at a low, low-middle level; with Changsha City and the Western Hunan Area as dual cores, it reflects obvious “core-edge” characteristics; (3) Quality index, market attention level, connection breadth, and distance index jointly affect the symbiosis intensity of scenic spots. Among them, the quality index, market attention level, and connection breadth all have positive impacts on the symbiosis intensity, whereas the distance index has a negative impact on it. Finally, this paper discusses how to improve the symbiosis intensity of scenic spots and promote the mutual benefit and symbiosis development to provide a theoretical basis and practical reference for the promotion of the sustainable development of regional tourism.