Abstract: [Objective] The paper aims to research the extraction of urban green space information.[main content] Nearly 10 years of domestic and inernational research information extraction green reviewed, found mainly in the low-resolution images with pixel-based approach, high-resolution image of the main object-oriented methods.The low-resolution image acquisition cost is lower than the high-resolution images.Based on the presence of salt and pepper phenomenon like element method,accuracy is not high, but easy to operate.Object-oriened approch complicaed operaion,but high accuacy to meet the meaning of landscape ecology.[conclusion]Extraction of urban green there is insufficient information, does not meet the classification criteria of urban green space system ,in furture studies also need to extract information green urban by urban green space system in accordance with the classification criteria.