Studies on soil aggregate loss in the process of soil erosion have an important significance in exposing mechanism of soil erosion. Rainfall intensity, as an important parameter in characterizing rainfall events, plays a significant role in soil erosion. A large number of studies have shown that there is a certain relationship between rainfall and composition of erosion sediment. However, most studies on soil aggregate loss in the process of soil erosion were conducted in the laboratory, which might affect some of the soil properties, especially the distribution of soil aggregates, when soil samples were collected and moved from the field to the laboratory. In this study, an in-situ field simulated rainfall experiment was conducted on a cropland in the typical black soil region of Heilongjiang Province to investigate characteristics of soil aggregate loss in the process of soil erosion. The experiment was designed to have three rainfall intensities, i.e., 30, 60 and 90 mm h–1 and a set duration, 40 min, for each simulated rainfall event. Variations of characteristic indices of soil aggregate loss, such as mean weight diameter (MWD), geometric mean diameter (GMD), fractal dimension (D), mean weight soil specific area (MWSSA), ≥ 1 mm soil aggregates (PA₁), ≥ 2 mm soil aggregates (PA₂) and ≥ 0.25 mm soil aggregates (PA_0.25), as affected by rainfall intensity, were analyzed. The runoff plots (10 × 1 m, each) of the experiment were deployed in a cropland on a sunny slope, 5° in gradient. The soil of the cropland was typical black soil 38.9% in clay, 55.3% in silt, 5.8% in sand and 28.8 g kg^-1 in organic matter, 1.10 g cm^-3 in bulk density and 6.65 in pH. Results show that rainfall intensity had some significant effects on runoff and soil loss. The ratio of soil loss in the first 20 minutes of a rainfall event to total soil loss increased with increasing rainfall intensity. The sediment resulting from a rainfall event, 30 mm h^-1 in intensity, was dominated with <0.25 mm soil aggregates, which made up 90.0% of the total soil aggregate loss; the sediment from a rainfall event, 60 mm h^-1 in intensity, was mainly composed of <0.25 and 0.5~1 mm soil aggregates, which accounted for 63.7% of the total soil aggregate loss; and the sediment from a rainfall event, 90 mm h^-1 in intensity was mainly of <0.25 and 2~5 mm soil aggregates, which amounted to 31.7% and 31.2% of the total soil aggregate loss, respectively. Rainfall intensity was found to have very significantly positive relationships with PA_0.25, PA₁, PA₂, MWD and GMD, but very significantly negative ones with MWSSA and D. It was also found that indices of PA₁， MWD and GMD are all good indicators characterizing soil aggregate loss in croplands in the typical black soil region of Northeast China.