Image enhancement is the basis for target detection and identification.In order to detect infrared target well,we propose an improved algorithm by using ridgelet transform which is a kind of multi-scale geometric analysis tool and is especially suitable for describing the 2-D signals.Firstly coefficient transform principle of ridgelet transform is introduced.Then adaptive enhancement algorithm is proposed.Tensile scale and compressing scale of coefficient in ridgelet transform domain are the key points of the method.Statistics is used in processing of transform to format characteristic data for consistent match,and the algorithm is assessed with sign-test method.The algorithm improves the target′s detail characteristics.Finally images are reconstructed and compared with those processed with other traditional methods.Our enhancement method is proven effective by experimental results.