Abstract: In semi-arid of the Loess hi1ly and gully region, the precipitation is the main limited factor for vegetation growth. The fish-scale pit has been popularized as one kind of runoff catchment measure. In order to study the catchment function of fish-scale pit in rainy season, continuous monitoring of soil moisture was carried out on the typical spots. The results showed that during July and August, the average soil water contents inside the fish-scale pits were below the levels of external slope; the 20-40 cm soil layer in the fish-scale pits was the main use of soil water, and the 40-60 cm soil layer was the main runoff catchment; the effect of each fish-scale pits was different, which was mainly in the runoff periods. As a result, the catchment effect of each fish-scale pits was influenced by layout mode, construction technology and other factors.