A infrared small target detection method based on FACET filtering weighted local contrast is proposed to address the problem of low contrast between targets and background and high edge brightness in infrared images under low altitude and complex backgrounds. Firstly, the target candidate pixels are obtained through FACET filtering operation. Then, local contrast is calculated by the ratio of grayscale differences between the target and background regions, and a weighted function is designed based on the heterogeneity of the target and background to enhance target saliency and suppress background. Finally, the real target is extracted through adaptive threshold segmentation. The performance of the algorithm is compared and analyzed with different algorithms on five sets of real infrared small target image datasets. The experimental results show that the algorithm proposed has good detection performance in different low altitude complex scenes.