Land subsidence monitoring is of great significance for urban development and planning, and the use of remote sensing data for land subsidence monitoring is currently one of the research hotspots. Traditional InSAR, D-InSAR and other technologies have certain technical limitations. This paper proposes a method based on SBAS-InSAR, which uses 236 Sentinel-1A data from June 2015 to June 2024 in the Maoming City, Guangdong Province to obtain time-series land subsidence results in three key survey areas: Maoming High-tech Zone, Shuidongwan New Area, and Binhai New Area. The results indicate that the High-tech Zone experienced significant subsidence in 2020, while the deformation was relatively gentle during the rest of the time period. During the research period, the Shuidongwan New Area continued to experience subsidence, becoming the area with the most severe subsidence, with a maximum cumulative subsidence exceeding320 mm. The Binhai New Area will continue to experience subsidence before 2023, but the subsidence rate will slow down after 2023. Research shows that surface deformation in the Maoming City is mainly influenced by construction activities, groundwater extraction, and geological tectonic activities. The research results of this article provide scientific basis for local governments to formulate disaster prevention and reduction strategies and optimize urban planning, and provide new technical support for land subsidence monitoring.