The effect of three land use patterns(forestland,garden plot,farmland )on the vertical distribution of total organic carbon(TOC)，particulate organic carbon(POC)and heavy fraction organic carbon(HFOC)in typical brown soil were studied by field sampling and laboratory analysis methods.Soil samples(0~20 cm,20~40 cm and 40~60 cm )were collected from each of land use patterns.The results showed that the conversion of forestland to garden plot and farmland decreased the content and reserves of TOC in all levels significantly.Compared with the TOC distribution share and ratio of the forestland,the TOC distribution of garden plot were transferred to the upper form middle and lower layers,but the TOC distribution of farmland were transferred obviously to the middle and lower layers.The relative number of POC decreased with increasing of the depth under three land use patterns.After the conversion of forestland to garden plot and farmland,the POC of garden plot on the middle and lower levels were significantly decreased by 6.67 and 1.70 percentage point,respectively;While the farmland at all levels were significantly reduced by 13.65,5.43 and 3.03 percentage point,respectively.The relative number of HFOC increased with the soil depth and the intensity of intervention.The increasing relative number of HFOC under farmland and garden plot use patterns showed that 5.77 and 4.00 percentage point in the upper,10.44 and 6.40 percentage point in the middle,7.35 and 3.92 percentage point in the lower,respectively,and significant differences.Therefore,we should pay attention to the input of organic matter after the conversion of forestland to garden or farmland,in order to reduce or mitigate the losses that caused by reclamation of organic carbon and its unreasonable distribution.