Aiming at the matter that pedestrian detection in the autonomous driving system is vulnerable to the influence of the external environment and the detector supported single sensor modal detector has poor performance beneath the condition of enormous amendment of unrestricted light-weight, this paper proposes a fusion of light and thermal infrared dual mode pedestrian detection methodology. Firstly, 1 × 1 convolution and expanded convolution square measure are introduced within the residual network, and also the ROI Align methodology is employed to exchange the ROI Pooling method-ology to map the candidate box to the feature layer to optimize the Faster R-CNN. Secondly, the loss performance of the generalized intersection over union (GIoU) is employed because of the loss performance of the prediction box positioning regression; finally, supported by the improved Faster R-CNN, four forms of multimodal neural network structures square measure designed to fuse visible and thermal infrared pictures. According to experimental findings, the proposed technique outperforms current mainstream detection algorithms on the KAIST dataset. As compared to the conventional ACF + T + THOG pedestrian detector, the AP is 8.38 percentage points greater. Compared to the visible light pedestrian detector, the miss rate is 5.34 percentage points lower.