This survey aims to gain an in-depth understanding of the current state of research on multimodal object detection in low-light environments. Firstly, we introduce the background of multimodal object detection in low-light environments, discuss the challenges faced by this task, and provide an overview of existing related review literature. Secondly, we comprehensively introduce the multimodal sensor combinations and their specific models, benchmark datasets, and evaluation criteria currently applicable to multimodal object detection tasks in low-light environments. In addition, we conduct a comprehensive investigation of multimodal detection methods such as visible-infrared and visible-LiDAR, as well as other multimodal detection methods, and conduct in-depth analysis and discussion on the potential and challenges of each method. Finally, we present a quantitative comparison of the most advanced methods on widely used benchmark datasets and discuss research trends, important issues, and future research directions. • This paper highlights multi-modal needs due to single-modality limits in low-light detection. • The paper introduces low-light multimodal datasets and sensors, analyzing their pros and cons. • This study summarizes research on low-light detection using various sensors. • Analyzes performance of visible-infrared and visible-LiDAR object detection methods.