The contribution of medium elements，including calcium，magnesium and sulfur，to agricultural productivity was of great importance. The objectives of the present study were to investigate the characteristics of soil exchangeable calcium，exchangeable magnesium，available sulfur and their effects on main crop yields at national and regional scales，so as to provide theoretical basis for the management of medium elements and rational fertilization in cultivated land at national and regional scales.Based on the data from 697 cultivated land quality monitoring sites across China，this research compared and analyzed the characteristics of soil available calcium，magnesium and sulfur and their effects on crop yields at national and six major grain production region scales(the Northeast，North，Northwest，Southwest of China，Yangtze River Basin and the South of China)in 2016 and 2021. Compared to 2016，the average contents of soil exchangeable calcium and exchangeable magnesium did not change significantly，and soil available sulfur content decreased by 27.3% on average at notional scale in 2021. Exchangeable calcium，exchangeable magnesium and available sulfur were mainly related to soil pH and organic matter(OM).The interannual variation characteristics of soil exchangeable calcium，exchangeable magnesium and available sulfur in six major grain production region scales were different. In Northeast China，the contents of soil exchangeable calcium and exchangeable magnesium increased by 25.5% and 52.4% on average，respectively，which was mainly related to pH.Soil available sulfur content decreased by 47.8%，mainly related to available potassium. In North China，soil exchangeable calcium content decreased by 11.8%，which was mainly related to pH. In Northwest China，the contents of exchangeable calcium，exchangeable magnesium and available sulfur decreased by 64.0%，54.0% and 30.4%，respectively. Calcium was mainly related to total potassium，magnesium was mainly related to total phosphorus，while there was no significant correlation between sulfur and soil chemical properties. In Southwest China，soil available sulfur content decreased by 30.0%，mainly related to pH and organic matter. In the Yangtze River Basin，the contents of exchangeable magnesium and available sulfur decreased by 52.0% and 15.7%，respectively，mainly related to pH and organic matter. The contents of three available medium elements did not change significantly in the south of China，and they were mainly related to pH and organic matter. At national scale，the rice yield was positively correlated with soil exchangeable calcium and exchangeable magnesium contents; corn yield was positively correlated with soil exchangeable magnesium and available sulfur contents; there was no significant correlation between wheat yield and three medium elements contents. Wheat yield was positively correlated with soil exchangeable calcium and exchangeable magnesium contents at pH ≤ 7.0. When pH>7.0，there was no significant correlation between wheat yield and soil exchangeable calcium and exchangeable magnesium contents. The wheat yield was not related to soil available sulfur content whether the soil was acidic or alkaline. In summary，the contents of soil exchangeable calcium and exchangeable magnesium did not change significantly，and the available sulfur content decreased significantly across China during the year from 2016 to 2021.The contents of these medium elements were mainly related to soil pH and organic matter. There were significant differences in the variation and influencing factors of soil medium elements，and their impact on main crop yields across six major grain production areas. Optimized medium element fertilization could help improve crop yield at regional scale.