The ecological construction project is an important measure to control soil erosion and restore soil fertility in the Loess Plateau of China. It is of great importance to research the effects of ecological restoration measures (ie.

returning farmland to forest and grassland?or terraces) on the soil organic carbon (SOC) and soil total nitrogen (TN)

which helps to evaluate the carbon sequestration capacity and nitrogen fixation capacity and even the cycles of carbon and nitrogen accurately. In this study

soils were sampled in the typical small watershed with five different ecological construction types in Loess Hilly Region

to study the distribution of SOC and TN contents in different soil depths of 0—100 cm. Four land uses conversions included from sloping farmland into woodland

grassland

shrub land and terraces respectively. The results showed that both the land use changes and soil depth had significant effects on SOC and TN (P <0.01). The SOC and TN in woodland and shrub land were enriched in the 0—20 cm

whereas both of which were enriched in the 0—40 cm in grassland. In the terraced fields

the SOC were mostly enriched in the 0—20 cm

but no enrichment of TN was observed. Sloping farmland had no enrichment of SOC and TN. The SOC and TN contents and reserves would be increased after different ecological restoration measures. There were very significant correlations between SOC and TN in forest land and grassland

while the correlation was significant in shrub

and moderate in slope land and terraces. This study could provide a scientific basis for improving soil carbon and nitrogen prediction in the loess hilly region and promote a rational planning for regional ecological construction.