Many successful semantic segmentation models trained on certain datasets experience a performance gap when they are applied to the actual scene images, expressing weak robustness of these models in the actual scene. The training task conversion (TTC) and domain adaption field have been originally proposed to solve the performance gap problem. Unfortunately, many existing models for TTC and domain adaptation have defects, and even if the TTC is completed, the performance is far from the original task model. Thus, how to maintain excellent performance while completing TTC is the main challenge. In order to address this challenge, a deep learning model named DLnet is proposed for TTC from the existing image dataset-based training task to the actual scene image-based training task. The proposed network, named the DLnet, contains three main innovations. The proposed network is verified by experiments. The experimental results show that the proposed DLnet not only can achieve state-of-the-art quantitative performance on four popular datasets but also can obtain outstanding qualitative performance in four actual urban scenes, which demonstrates the robustness and performance of the proposed DLnet. In addition, although the proposed DLnet cannot achieve outstanding performance in real time, it can still achieve a moderate performance in real time, which is within an acceptable range.