Abstract:13C pulse labeling technique was used to trace the fate of 13C in peanut-soil system and assess the effect of different fertilization methods on the distribution of photosynthetic carbon. Four treatments were set up in this experiment, namely NPK (normal fertilization method), NPKS (normal fertilizer and corn straw), NPKA (normal fertilizer and humic acids) and CK (no fertilizer). Results showed that the differences were not significant in total peanut biomass among different treatments. However, the root biomass of NPKA was 22.04%, 19.47% and 53.38% higher than those of CK, NPK and NPKS, respectively. Abundance of 13C in aboveground was highest in NPKS while NPKA had highest 13C abundance in soil. 13C concentration showed no significant difference among treatments in aboveground but concentration of NPKA was higher than NPK in roots and was highest in soil. Distribution ratio of 13C of NPKA was lower than those of other treatments in aboveground and was highest in soil, showing that application of humic acids can significantly promote the transport of peanut photosynthetic carbon to the underground.