In order to explore the promotion effects of different carbon sources on soil carbon，a study was carried out on the influence of different carbon sources on soil carbon balance in the growing season of flue-cured tobacco，aiming at providing theoretical basis for the regulation of soil organic fertilizer application.A field experiment was conducted in Panzhihua city，Sichuan province，using flue-cured tobacco as tested crop.Five fertilization treatments were set up:control(no organic fertilizer)，straw，farmyard fertilizer，oil cake，farmyard fertilizer and oil cake，and repeated for 3 times.Field monitoring was conducted using VaisalaMI70 soil respiration measuring system，and environmental conditions were observed at the same time.The carbon sequestration of flue-cured tobacco roots was measured.The results showed that :1)In the growth season of flue-cured tobacco，the soil respiration dynamics of tobacco plants showed an inverted “S” pattern，at first it went down，then rose and fell again.The application of organic fertilizer increased the soil respiration intensity，especially in the early application of organic fertilizer.2)The average carbon emission of flue-cured tobacco in the growing season was 385.84 kg·hm-2，and the carbon emission of different treatments was 293.11，396.9，363.36，422.98，452.84 kg·hm-2，for the treatment of contrast，straw，farmyard fertilizer，oil cake，oil cake+farmyard fertilizer，respectively.3)The decomposition rate of different carbon sources was significantly different，with a decomposition coefficient of 0.22～0.42 in the growing season.The decomposition coefficient of straw and farmyard fertilizer was lower than that of oil cake.4)The application of organic fertilizer had no obvious effect on the improvement of root carbon accumulation in flue-cured tobacco.Farmyard fertilizer as well as farmyard fertilizer and oil residue mixed fertilizer significantly increased the root carbon accumulation of flue-cured tobacco compared with the treatment of straw.5)In the local farming，the 56.42% roots of flue-cured tobacco remained in soil though the whole growth period，which compensated soil carbon by 260.56 kg·hm-2.The root carbon of flue-cured tobacco is the main source of soil carbon under conventional fertilization.6)In conventional fertilization，the tobacco soil under single application of fertilizer presented carbon source，while the tobacco soil under organic and inorganic fertilization presented carbon sink.The application of organic fertilizers can improve soil carbon balance and reduce carbon loss.Up to a point，the application of farmyard fertilizer mixed with oil cake can also promote the growth of flue-cured tobacco root carbon accumulation.