To enhance the perception of small objects,based on the F-PointNet network,the FDG-PointNet 3D object detection model is proposed by combining dense connection and Gaussian distance features. Gaussian distance features is fused as additional attention features,and it effectively solves the low accuracy of instance segmentation in the F-PointNet network and enhances the noise filtering in the point cloud view cone. Based on the characteristics that dense connection can enhance feature extraction, the dense connection is used to improve PointNet++ network and enhance point cloud feature reuse. It alleviates low degree of feature extraction and gradient disappearance for small objects in the feature extraction process,and improves the accuracy of 3D object bounding box regression. The experimental results show that the proposed algorithm outperforms the benchmark method F-PointNet in three levels (easy,moderate,and hard) for the detection of car,pedestrian,and cyclist,which can achieve the average detection accuracy of 71.12%,61.23%,and 55.71% for car,pedestrian,and cyclist at moderate level. It has the most significant improvement for pedestrian detection,and can increase 5.5% and 3.1% at easy and moderate levels,respectively. In summary,compared to F-PointNet algorithm,the proposed FDG-PointNet algorithm effectively solves the low accuracy of small objects detection and has strong applicability. © 2024 Editorial Board of Jilin University. All rights reserved.