Objective Southwest China (Yunnan, Guizhou, Sichuan, and Chongqing) is highly sensitive to soil erosion, necessitating urgent simulation and prediction of future land use changes to support regional ecological protection and land management decisions.

Methods Based on MCD12Q1 historical land use data (2001−2020) and LUH2 future data, the patch-generating land use simulation (PLUS) model was used to simulate land use distribution from 2020 to 2100 under three Shared Socioeconomic Pathway-Representative Concentration Pathway (SSP-RCP) scenarios: SSP1-RCP1.9 (sustainable development, SSP119), SSP2-RCP4.5 (medium development, SSP245), and SSP5-RCP8.5 (high-speed development, SSP585). Spatiotemporal variation characteristics of land use change in this region during the 21st century were analyzed using land use dynamic degree, transition matrices, and spatial expansion analysis.

Results 1) Historically (2001–2020), the comprehensive land use dynamic degree was 0.47%, indicating a relatively high change intensity. Forestland increased significantly by 42 191 km² (reaching 47.73% coverage), primarily converted from grassland (−52 614 km²). Construction land surpassed unused land to become the fourth largest category, with its expansion concentrated in urban agglomerations such as the Chengdu-Chongqing economic zone. 2) The PLUS model demonstrated high accuracy with Kappa = 0.85, overall accuracy (OA) = 0.91, figure of merit (FoM) = 0.18. From 2020 to 2100, grassland was the primary land use type converted to other uses under all scenarios. Construction land exhibited an inverted U-shaped trend, peaking in the 2050s before decreasing. 3) Under the SSP119, land use change intensity was the highest, with the peak comprehensive dynamic degree reaching 1.71%. Forestland and cropland increased by 57.33% and 66.96%, respectively. Forestland covered most areas except the Sichuan Basin, and cropland expanded in northwestern and eastern Sichuan and eastern Yunnan. Grassland area experienced a net decrease of 96.23%. Under the SSP245, the change intensity was relatively low, with comprehensive dynamic degree ranging from 0.08% to 0.34%. Forestland and cropland increased by 10.18% and 18.40%, while grassland decreased by 19.21%. Under the SSP585, the change intensity was high before 2040 and then slowed down. By 2100, the area of each land use type converged with that under the SSP245, and construction land in urban agglomerations exhibited high-intensity concentric expansion.

Conclusions The PLUS model can reliably simulate future land use change in the complex terrain of Southwest China. The simulation results reveal the spatiotemporal characteristics of land use change in this region under different development scenarios, providing robust scientific support for territorial spatial planning (e.g., delineation of ecological protection red lines) and land management strategy formulation (e.g., soil erosion prevention and control).