Soil samples were collected from croplands and vegetable lands in Quzhou County of Hebei, Shouguang County of Shandong and Shunyi District of Beijing for comparison between lands under two different patterns of land use at the same location in content, distribution in the soil profile and composition of DOC. Results show that in the topsoil soil organic carbon (SOC) was 3.16 ~ 47.4% higher and total Nitrogen (TN) 3.09 ~ 64.1% higher in the vegetable fields than in the crop fields, while soil C/N and pH lower. The DOC content in either crop or vegetable fields decreased significantly with soil depth. The mean of the DOC contents in the topsoils of the vegetable fields was 1.70 times as high as that of crop fields. A significantly positive relationship was observed between SOC and DOC. In terms of composition of the DOC, its fractions followed an order of Hydrophilic matter (HIM) > Hydrophobic acids (HOA) > Hydrophobic neutrals (HON) > Hydrophobic bases (HOB) in the top soil (0~30 cm) in both crop fields and vegetable fields. In vegetable fields, HOA accounted for 19.0~26.7%, while in crop fields for 14.83~16.42%; The difference between the two fields in Shouguang was quite significant (p<0.05), which is probably related to the higher SOC contents and lower pH in its vegetable field. The HOM/HIM ratio was 0.30, 0.39 and 0.41 in the vegetable fields of the three regions, which may suggest that the vegetable fields vary in humification degree. In conclusion, transformation of crop fields into vegetable field significantly affects quantity and quality of DOC.