To explore differences between soil in open-field without salt accumulation and soil in greenhouse with salt accumulation in acidification, simulation of soil acidification and salt leaching was conducted of the soils for analysis of changes in soil acidity caused by salt leaching. Results showed that salt leaching lowered electric conductivity (EC), available Ca (A-Ca), exchangeable acid (EA), effective cation exchange capacity (CEC) and active manganese (Ac-Mn) significantly, had little effect on or increased active aluminium (Ac-Al) and iron (Ac-Fe), base saturation percentage (BSP) and pH significantly. The EA, Ac-Al and Ac-Fe increased significantly, while the Ac-Mn and CEC decreased significantly with a decrease in pH of soil with and without salt accumulation. Moreover, when a certain amount of EA appeared, BSP declined significantly with lowering pH. All these indicated that acidifications in the two soils are the same in nature, but when an equal amount of acid was added into the two soil, acidification of the plow layer of the soil with salt accumulated in greenhouse was accelerated, bringing about more severe acid damage and making the soil liable to have salt accumulation. It is, therefore, suggested that in managing soil acidification in greenhouses, it is essential to avoid introduction of more salt so as to prevent aggravation of salt damage.