This study aims to use SQI to evaluate the quality of the saline acid sulfate soil in Can Gio district, Ho Chi Minh City, Vietnam, on different land use types, including annual crops (AC), perennial crops (PC), rice land (RL), aquaculture land (AL), and natural soil (NL). The study employs the SQI formula to assess the soil quality index of 170 samples from two distinct soil layers (0–30 cm and 30–60 cm). The 17 soil properties relate to acidity, salinity, toxicity, and nutrition. In the surface layer (0–30 cm), the land use type of AL has the highest SQI (0.57), followed by NL, AC, and PC (0.53–0.55). The land use type of RL exhibits the lowest SQI of 0.50. In the deeper layer (30–60 cm), the difference in SQI among the land use types becomes less pronounced. The land use type of AL has high toxicity (0.15) and a high nutrient accumulation (0.21) in the surface layer. The land use type of RL indicates that the soil exhibits signs of recession, with the lowest SQI values in toxicity (0.12) and nutrition (0.18). For land close to the coast, certain soils can become more acidic and salty due to processes like pyrite oxidation and saline intrusion, which can lower soil pH and raise salt and toxic levels, especially in the top layer. The effectiveness of using SQI to evaluate soil quality was demonstrated, thereby supporting the management of soil quality, particularly in cases such as coastal saline areas. However, it is necessary to evaluate the effectiveness of the index in proposing recommendations for soil improvement.