With rapid urbanization, land use change has shown a close negative relationship with ecosystem services, especially in urban agglomerations. Thus, rational urban planning involving key ecosystem services (ESs) in highly urbanized areas has become urgent and crucial in urban ecology and urban sustainability studies. Taking Guangdong–Hong Kong–Macao Greater Bay Area (GBA) as a study area, we simulated land use change considering different ecosystem service protection scenarios over the years 2020-2050 by adopting integration of the Markov chain model and the future land use simulation (FLUS) model. And then we quantified the impact of land use change on key ESs in the GBA. Under the simulation scenarios, the urban land will enlarge from 4286.00 km2 to 4802.25 km2, with a growth rate of 12.05%. Compared to the baseline (BA) scenario, the ESs could be maintained under other simulation scenarios, especially the integrative conservation (IC) scenario. Under the IC scenario, the habitat quality index, water conservation capacity, soil conservation capacity, and carbon sequestration will increase by 0.036, 7×104 t, 5.11×106 t, and 0.93×106 t when compared to the BA scenario. Newly increase urban land caused extensive loss of farmland and forestland, and mainly distributed in megacities and supercities surrounding areas. The study shows that different development modes are the crucial driver of loss of key ESs. In order to maintain the key ecosystem service functions of the whole GBA region, the coordinated development among megacities, supercities and largecities, especially the development of largecities, will play a critical role
