The light field reconstruction aims to recover the 4D light field from the 3D focal stack, so it is a severe incomplete data reconstructing problem. The Landweber iteration is a general method to find the least-square solution of the discretized linear system, which is widely used for solving such problem. The relaxation strategies of the Landweber iteration are essential for both accelerating iterative convergence and decreasing errors. As a fast and non-approximate linear-time method, the fast guided filtering has good edgepreserving smoothing properties. It can be incorporated into the light field reconstruction process to improve the precision of the reconstructed results. In this paper, we propose a filter-based Landweber iterative method by introducing the optimized relaxation strategy and the fast guided filter. Specifically, the updated image in the iteration step contains the guidance image and the image obtained by the Landweber iteration, which makes the proposed method flexible. The experimental results show that the proposed method is more practical and effective compared with the relevant reconstruction methods.INDEX TERMS Light field reconstruction, Landweber iteration, relaxation strategy, the fast guided filter.