本文在黃河中游地區選擇了50多個水文測站流域，流域面積從500平方公里至2,500平方公里，分別代表7種不同自然地理類型。在流域降雨、泥沙及環境特徵資料獲得的基礎上，建立了流域產沙量與降雨季節性、年際變化和年降雨量之間關係。結果表明，以不同自然地理類型流域為參數，產沙量與降雨季節性變率和年際變率之間有著相當好的正相關關係，而且由沙黃土、砒砂岩流域，經黃土流域、黃土與基岩流域，到基岩山地流域，曲線的斜率漸趨減小，曲線的位置由上而下呈有序的排列。流域產沙量與年降雨量之間關係遵循Langbein-Schumm曲線，但是由沙黃土、砒砂岩流域向基岩山地流域過渡，流域產沙量峰值以及峰值出現所需要的降雨量漸趨減小。流域產沙量隨年降雨的上述變化是流域降雨、地面物質、植被和地貌發育程度等共同作用的結果。本文用VSD指標表示流域地表環境特性，統計表明，流域產沙量與VSD之間有著相當好的正相關關係。逐步回歸分析進一步表明，植被是影響流域產沙量最重要的因數，其次依次是流域溝壑密度和地面物質，而降雨因數沒有進入方程。這說明，與前三個因數相比，降雨對流域產沙量的影響是次要的，從而解釋了為什麼流域產沙量與降雨關係會出現明顯區域差異的原因。

More than 50 river basins with areas ranging from 500 to 2,500 km2 were chosen for an analysis of the relationships between sediment yield and rainfall in the middle reaches of the Yellow River. The basins are categorized into 7 physiographical types. A set of data on sediment yields and rainfall characteristics, surface materials, vegetation covers and morphological features of these basins were collected by using remote sensing data combined with field checks and indoor analyses. Based on such data, a correlative analysis was made between sediment yield and seasonal and annual variations of rainfall and annual average rainfall. It was shown that good positive relationships existed between sediment yields and seasonal and annual variations of rainfall, but different curve slopes and positions were observed when different types of physiographical conditions were taken as parameters. It can be clearly seen that the slopes of the curve lines tend to decrease with their positions, moving gradually downward in an orderly fashion for different types of basins, beginning with the basin of mixed sandy loess and heavily weathered siltstone and moving sequentially to the loess basin, the basin of mixed loess and bedrocks, and finally to the bedrock hill basin. Variations of sediment yields with annual average rainfalls followed the Langbein-Schumm law, but as one moves from the basin of mixed sandy loess and heavily weathered siltstone to the bedrock hill basin, the peaks of sediment yield and the threshold rainfall needed for the peaks declined gradually due to the joint effect of rainfall, surface material, vegetation cover and basin morphology. The environment features of river basins had an important effect on the relationship betweeen specific sediment yields and rainfall index. An integrated index, VSD, based on vegetation covers, surface materials and morphological features, was used to indicate the resistance of river basin environment to erosion and specific sediment yields. It was revealed that specific sediment yields were positively related to the index VSD. Furthermore, a stepwise regression was carried out which showed that the best correlation occurred between specific sediment yield and vegetation cover, followed by drainage gully density and surface material. Rainfall did not enter into the equation. The relationship between specific sediment yield and rainfall was not as good as commonly expected. Compared with the three main factors pf vegetation cover, drainage gully density and surface material, the effect of rainfall on sediment yield is only of secondary importance. This is the reason why the relationships between sediment yields and rainfalls varied markedly from one region to another in the Middle Yellow River Basin.