Free-range cattle farming has resulted in considerable challenges to the ecology and environment in pastoral areas, particularly in relation to local water quality in pastoral lakes. This study investigated the impact of cattle manure (CM) on pasture water quality evolution in a typical pasture in arid regions, especially the pollution contribution of nitrogen (N) and phosphorus (P). Fresh cattle manure (FCM) and dry cattle manure (DCM) were analyzed in a traditional pasture. The results indicated that FCM contained higher N and total organic carbon than DCM. Leaching experiments revealed that FCM released more N and P into pastoral water than DCM. However, soil adsorption and desorption experiments demonstrated that soil in pastoral areas reserve N and P from CM, reducing N and P water pollution contribution. Furthermore, the predominant organisms in FCM, such as Proteobacteria and Bacteroidota, inhibited the release of N and P from CM. The quantified pollution load from CM to water quality deterioration revealed that the contribution of N and P inputs was below 1 %, indicating that CM is not a major driving factor for water quality decline. Therefore, although CM contributes to pollution load, its impact on water quality evolution is limited compared to that of other anthropogenic factors (local industry and agriculture). This study provides new insights into integrated management strategies for protecting the ecological health in pasture.