The present invention discloses a remote sensing image power transmission line corridor forest region extraction method. The method comprises the steps of (1) training an SVM classifier: extracting a scene unit training sample from a remote sensing training sample and using an artificial visual way to define the scene category of each scene unit training sample and carrying marking by using a mark number; extracting the global characteristic of each scene unit training sample; and combining the scene category mark number of the scene unit training sample and the global characteristic to train the SVM classifier, (2) using the trained SVM classifier to classify the remote sensing image test data: extracting a scene unit from the remote sensing image test data; extracting the global characteristic of each scene unit; and using the trained SVM classifier to extract a forest region based on the global characteristic combination of the scene units. According to the method, the completeness of extracted object description can be enhanced, and thus the accuracy of the forest area extraction is improved.