Seatbelt detection is an important topic in intelligent transport systems. The accuracy of seatbelt detection in traffic video surveillance is affected by many factors, such as complex road environments, lighting, weather, direction of the camera, etc., which bring difficulties for traditional image processing methods. We propose a seatbelt detection method based on classification using convolutional neural networks. Dense residual blocks are used to avoid gradient dispersion and information loss during the network training. A two-level attention mechanism is also introduced to further improve the network performance by simultaneously modeling the correlation among different feature channels using channel attention mechanism, and correlation among different pixels within the feature map using pixel attention mechanism. To make the whole system complete, we added the driver area localization module, which is accomplished using the YOLOV3 model. Small images concentrated on the driver location, which are obtained through the localization operation from larger images, are passed into the classification network for seatbelt detection. We compared the proposed method with several other methods. Comparative results show that the proposed method has higher accuracy and is more robust for seatbelt detection for complex environments.