Aiming at the problem of the anomaly point sensitivity of collaborative representation for hyperspectral anomaly target detection algorithm, an improved collaborative representation for hyperspectral anomaly detection based on background refinement is proposed. The expansion of mathematical morphology is used to eliminate the anomaly points that may exist in the local backedground model, so that a more pure backedground dictionary can be obtained, which can effectively eliminate the negative influence of anomaly points on the detection and improve the detection accuracy. The algorithm is applied to make simulations on hyperspectral data and compared with the existing algorithms, and the results show that it can realize a better detection effect.