Currently our country is being in the crucial time, which is a historical stage that the average GDP per person develops from 1,000 US dollars of low income countries to 3,000 US dollars of medium income countries. The international experience indicates that it is a very important historical span stage now. Not only a stage developing fast for basic condition, but also a stage contradiction of the population, resources and environment and so on pop out, and bottleneck restriction enhanced. If it be treated improperly, the economical growth to pace back and forth will possibly appears, even a series of social problem. Analysis on benefit and loss of soil and water conservation for construction projects, means that according to the request of scientific development view, harmonious society and the person and nature get along harmonious, Studying thoroughly on the benefit and loss of soil and water conservation of construction projects, exploring and establishing appraisal index system of soil and water conservation. Analyzing and appraising the benefit and loss of soil and water conservation for construction projects qualitatively, quotably, comprehensively, systematically and scientifically. It can provide the scientific basis for technical demonstration and administrative examination for soil and water conservation scheme.The study apply economic cost-benefit analysis, environmental impact economic cost-benefit analysis and system theory, and using the analysis methods such as Analytic Hierarchy Process (AHP), the Key Performance Index Analytic Method(KPI) and Delphi Method (the Delphi method). In China it's the first time to propose the benefit and loss concept of soil and water conservation for construction projects. Take this as the target level, it has established benefit and loss analysis index system of soil and water conservation for construction projects, which constituted of 7 appraisals criteria level, 29 targets levels and 51 variables levels, including the land resource impact, the water resources impact, the ecological environment impact, the water and soil conservation function impact, water and soil erosion of peripheral and the downriver impact, the project peripheral land and the environmental effect, the water and soil conservation cost and so on. According to the theory and method, putting up benefit and loss of soil and water conservation for 12 industries including road, railway, water conservancy, electric power, mining and so on and 500 typical construction projects throughout the country. It can provide method and illustration for different region and organization to analysis benefit and loss of soil and water conservation. Based on systematical and comprehensive analysis on benefit and loss of soil and water conservation for construction projects, the study propose the concept of soil and water loss impact index for construction projects for the first time and make the key index and variable of soil and water loss fitting to a mathematic model, and compute soil and water loss impact ration accurately. It can apply the simple and operable compute and analysis method for scientific demonstration, appraisement and judge, and measure and calculate the soil and water loss impact index of twelve different industries and projects. It summarizes the regular result, simultaneously provide the methods and illustration of calculating, analysis, judge for design and research institute, consulting and evaluating organization and different administrative decision-making department.This research proposed the definition and method about analysis of benefit and loss of water and soil conservation for construction projects and soil and water loss impact index. Calculating, analyzing, and validating the construction example. It indicates that the result is in accordance with the fact, and the theory and method is feasible. The road, railway, water conservancy, water and electricity, mining and so on have more impact on soil and water loss.