In order to elucidate the relationships between runoff parameters and variation in rainfall, we compared the volume, dissolved organic carbon (DOC) concentration, and DOC flux of runoff from Castanopsis carlesii (C.carlesii) secondary forest (SF) and from SF plots converted to young plantation (BC) or assisted naturally regenerated young forest (NR) after individual rainfall events. Our results indicated that the volume of the BC runoff was 1.5 to 19.0 times that that of the SF runoff, depending on the specific rainfall event. The total accumulated volume of the BC runoff during the research period was 5.9 times that of the SF runoff. However, neither the per-event nor the accumulated volume of the NR runoff differed significantly from those of the SF runoff. Meanwhile, the DOC concentration of the NR, BC, and SF runoff ranged from 5.9 to 18.4 mg/L, 4.3 to 13.5 mg/L, and 3.2 to 9.9 mg/L, respectively, and the mean DOC concentration of the SF runoff (12.6 mg/L) was 1.6 times that of the NR runoff (7.6 mg/L) and 2.4 times that of the BC runoff (5.3 mg/L). Regression analysis indicated that the DOC concentration of runoff water was significantly related to pre-rain soil water content, and DOC concentration was observed to increase with soil water content when the pre-rain soil water content was lower than 20.8%, and to decrease with soil water content when the pre-rain soil water content was higher than 20.8%. In addition, the DOC flux of the BC runoff was 0.7 to 5.4 times that of the SF runoff, and the total accumulated DOC flux from the BC runoff was 2.1 times that of the SF runoff. However, differences between the DOC flux of the NR and SF runoff were insignificant (P > 0.05), and for all three forests, the DOC flux was significantly (P < 0.05) related to rainfall. Therefore, the conversion of SF to BC reduced the DOC concentration of the runoff, but increased overall DOC flux owing to dramatic increases in runoff volume, whereas the conversion of SF to NR had no significant effects on DOC flux owing to the runoff's relatively low DOC concentration and volume.