Introduces the main method of remote sensing alteration information extraction is the ratio method,principal component analysis, spectral angle method,and using the anomaly threshold method to divide the threshold. The paper uses Landsat8—OIL as the data source. In order to extract the alteration anomaly information,firstly it establishes the mask model and then using the second principal component analysis method,finally using the threshold to divide the principal components.%对遥感蚀变信息提取常用的主要方法（比值法、主成分分析法、光谱角法）作了介绍，结合门限法划分异常阈值，以Land-sat8—OIL为数据源，采用二次主成分分析法，建立了掩模模型，并根据门限法对二次主成分分析法进行了异常阈值划分，提取蚀变异常信息。
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