In view of the poor mobility of urban landscape water body, being often in a closed or semi-closed state and easy to cause eutrophication, flow field optimization research was carried out on the typical urban landscape water body of Nanhu Lake in Yuncheng City, Shandong Province. First, the hydrodynamic and water quality coupling model for Nanhu Lake was constructed based on MIKE21 software, and the flow field and water quality in the lake area were simulated. Then, schemes of adding water-source heat pump outlets were proposed for improvement of the flow field and water quality in the lake area. The effects of different schemes were comparatively analyzed according to simulated results. The analysis results show that increasing the number of outlets may effectively improve the flow field distribution and water quality in Nanhu Lake, and the scheme of setting four outlets along the lake shore is effective for water environment improvement in Nanhu Lake, with the ammonia nitrogen mass concentration at the observation point decreasing by 59.7% on average, as compared with the original scheme.