| Shaanbei Loess Plateau, which is located in north Shaanxi from Beishan Mountain to Great Wall, is one of the landscapes of China Loess Plateau. There is a evolutional phenomenon to have been recognized in Shaanbei Loess Plateau from South to North .That is Luochuan district with the Loess Yuan (Platform Land) in south . Yan'an-An'sai district with the Loess Liang ( Ridges) mainly in middle and Shunde-Mizhi district with the Loess Mao (Rounded knolls) mainly in North .This frame and tendency is got and thought to coincide with the styles of their bedrock traditionalh?called conformability. But the conflict between them was appeared during our research in field and the discussion with others. It is followed that the former with the rolling bedrock, the mid with mild bedrock and the latter with the stable bedrock relatively. The conflict between two conclusion above arise, what relationship between loess landforms and their bedrock exist? This is related to other important issues, such as erosion protection, origin of loess landforms. development of local economy, and so on. With the simulating of the paleo-shape of the bedrock at office, research in field and application of GPS and GIS, The project has been studied.Meanwhile, Shaanbei loess Plateau is one of serious erosion. Usually .the summarization of erosion regulation and the mechanism outer faction in Lab are focused. The geological factors are important besides them, which are related to the loess landslide and evolution of gullies, specially for bedrock folds, bedrock joints and loess joints.In field, the data of the bedrock elevation in the three sheets combined with the research from south to north lively were got by GPS12XLC pocket locator, the type and its evolution of bedrock, loess landslides and distribution of hydrographical net were explored too.At office, the synthetic analysis and contrast were used including the simulating analysis about the data by Mapinfo 6.5, Software of GIS, discussion and communicationwith experts, in order to demonstrate and reveal the rules between the loess landforms and its pale bedrock landforms and the impact of structure on erosion interiorly in Shaan bei.After a lot of research and study, the following results have been attained:1. The unconformability between the loess landform of Shaanbei Loess Plateau and its bedrock shape was pointed out first after the full demonstration. The top of loess formation of the south part in Shaanbei is flat which likes "Platform", the shape of the bedrock is rolling that likes Ridge , and the bedrock bended to fold. The top of loess formation of the mid-part in shaanbei is rolling ,but the shape of the bedrock below begins to get flat, the top of loess formation of the north part in Shaanbei, loess Mao district, is much more rolling among them, however, its shape of the bedrock below is the flattest relatively likes the Platform shape of loess formation in south. From that new conclusion, we know the form of loess landform was built by erosion result from outside forces, which is historical and long-term.2. The unconformability between two sides has been analysed and belongs to better-level, the degree of subordination is 0.3308 through the fuzzy synthetic judgement on multi-factors.3. The loess landslide has been grouped to two types, one is single-side landslide the other is grid landslide. According to their styles, locations occurred and other controlling geological factors.4. There are different level and directional gullies and rivers. According to different controlling geological factors, they could be classified to three groups. And we pointed out the evolution of the first group which is the biggest level from north to south basically is limited by Shaanbei syncline structure, the evolution of second group which is the mid-level form east to west or from west to east basically is limited by the bedrock joints, the evolution of the last one,which belongs to small level is limited by loess joints.5. During the explorer, we know...
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