Sediment yield and delivery in the middle reaches of the Yellow River basin, especially at the loess hill and gully areas, is a primary cause of rapid bed accretion at the lower reaches of the Yellow River. Water flow, wind and freeze and thaw weathering are the important external erosion forces contributing to sediment yield and delivery. Of these three factors, freeze and thaw weathering has not received adequate attention from researchers, given the magnitude of its contributing effects. The environmental background, action mechanisms and representative modes of freeze and thaw weathering occurring in the loess hill and gully areas of the middle Yellow River basin are described and discussed. The sediment yield generated by freeze and thaw weathering in the sandstone area is about 1/2 the sediment yield generated by gully erosion in the area and 1/3 of the total sediment yield of stream catchments, with variations depending on gully lithology, gully sediment yield and other measured data.