Target detection is of great significance for polarimetric SAR (PolSAR) image applications, and independent target detection in a large scene can be considered as a sparse problem. In high-resolution PolSAR, the independent targets generally present a cluster of similar pixels, and therefore, the detection principle should include not only the internal characteristics but also the spatial information. This letter proposes an unsupervised adaptive convolution sparse representation (ACSR) method for PolSAR image independent target detection. The proposed method updates the dictionary to realize adaptive spatial information injection into polarimetric features, and then the independent target can be detected through the iteration. Two sets of high-resolution, full PolSAR images of unmanned aerial vehicle synthetic aperture radar (UAVSAR) system are used to validate the performance of the proposed method. The results indicate the potential of the proposed method in target detection of PolSAR image.