In this study, the sloping farmland soil of flue-cured tobacco was taken as the study object in Hongta District, Yuxi City, Yunnan Province, and four soil amendments including biochar, lignin, polyacrylamide and straw were selected to study their effects on soil organic carbon (SOC) and its components in different soil layers. The results show that the contents of SOC and its components in different growth stages of tobacco are in the order of mature stage < emerging stage < flourishing stage, and the contents of SOC and its components in different soil layers are in the order of 5-10 cm> 0-5 cm> 10-20 cm. The effects of adding high biochar (0.6%-47.0%) and straw (1.3%-38.2%) are more significant. Application of the above amendments can increase soil total nitrogen and total phosphorus concentrations to a certain extent, and the high amount of straw are the most significant (15.0%-32.8% and 37.6%-40.2%, respectively). The ratios of C:N, C:P and N:P of each treatment are in the range of 5.07-8.67, 3.91-6.12 and 0.34-1.00, respectively. Soil total nitrogen has significant positive correlation with soil total phosphorus (P<0.05) and SOC (P<0.01), respectively. There are extremely significant positive correlations (P<0.01) among SOC components. Soil depth, growth period and soil conditioner type have extremely significant effects on SOC components (P<0.01). The addition of biochar and straw have better effects on the improvement of SOC and its components as well as the ecological stoichiometric characteristics of soil nutrients, and in particular, the effects of adding 0.06 kg/m² biochar and 0.5 kg/m² straw are better.