【Objective】The Loess Plateau is the largest apple-producing area in China. Due to the serious aging of apple trees in recent years, the single variety structure, and the instability of China"s grain market, it has become a common phenomenon for orchards to be transformed into farmland on the Loess Plateau to ensure national food security. 【Method】In order to study the response characteristics of ecological stoichiometric ratio to orchard transformed into farmland, the farmland of 0 years ( 30 years orchard), 1 year, 3 years, and 5 years was selected as the research object in this study, with farmland cultivated with food crops set as the control group (CK). Soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) contents in the soil from 0-100 cm depth (every 10 cm layer, a total of 10 layers.) were measured, and their ecological stoichiometry ratios were calculated. The study also analyzed the influencing factors. 【Result】(1) With the increase of returning years, the mean values of SOC and