The urban-rural income gap is an important factor restricting the realization of common prosperity in the Yangtze River Economic Belt. In recent years, the tourism industry in the Yangtze River Economic Belt has been booming, and whether it has significantly reduced the urban-rural income gap has attracted more attention. Using the panel data of 110 prefecture-level cities in the Yangtze River Economic Belt from 2005 to 2020, the global spatial correlation test was firstly conducted, and then the spatial lag model was constructed. Finally, the panel threshold regression model was used to test whether the tourism development has a nonlinear effect on the urban-rural income gap. The main conclusions are as follows: Firstly, under the premise of global spatial correlation test, the tourism industry development of prefecture-level cities in the Yangtze River Economic Belt has played a significant role in narrowing the income gap between urban and rural areas. Secondly, the development of tourism, regional economic development and urbanization are selected as the threshold variables. The test results show that the impact of tourism industry development on the urban-rural income gap shows a double threshold effect. The three threshold variables all play an inverted “U” type change rule of first expanding and then narrowing the urban-rural income gap. It is proposed that the development potential of tourism industry in narrowing the income gap between urban and rural residents should be continuously tapped, the level of economic development should be continuously improved, and the urbanization construction process should be steadily promoted.