\begin{abstract}As a fundamental visual task, optical flow estimation has widespread applications in computer vision. However, it faces significant challenges under adverse lighting conditions, where low texture and noise make accurate optical flow estimation particularly difficult.In this paper, we propose an optical flow method that employs implicit image enhancement through multi-modal synergistic training. To supplement the scene information missing in the original low-quality image, we utilize a high-low frequency feature enhancement network. The enhancement network is implicitly guided by multi-modal data and the specific subsequent tasks, enabling the model to learn multi-modal knowledge that enhances feature information suitable for optical flow estimation during inference. By using RGBD multi-modal data, the proposed method avoids the reliance on the images captured from the same view, a common limitation in traditional image enhancement methods.During training, the encoded features extracted from the enhanced images are synergistically supervised by features from the RGBD fusion as well as by the optical flow task.Experiments conducted on both synthetic and real datasets demonstrate that the proposed method significantly improves performance on public datasets.