Abstract: The equipment's low tailings treatment capacity, due to the slow sedimentation speed of the ultra-fine-grained unclassified tailings in a certain mine, prevents it from meeting the filing requirements. Therefore, the research optimized the flocculation sedimentation parameters to accelerate the sedimentation and improve the tailings treatment capacity. Firstly, the factors affecting the settlement and the prediction optimization target were analyzed. On this basis, carrying out the single-factor flocculation settlement test, the study determined the experimental design range of the three factors of slurry concentration, flocculant solution concentration and flocculant addition amount, using the response surface method to optimize the target solid flux and predict the target underflow concentration as the response index to design 17 sets of proportioning tests. According to these tests, a multivariate nonlinear regression model was constructed to study the influence of interaction between multiple factors on the solid flux, and the flocculation settlement parameters of unclassified tailings slurry were optimized to maximize the solid flux and predict the underflow concentration under this parameter. The results showed that the solid flux was not only affected by a single factor but also by the interaction of multiple factors, and the interaction between slurry concentration and flocculant addition amount had the greatest influence on it. When the maximum solid flux of the optimization target was 0.755 9 kg/(m²·s), the slurry concentration was 25.36%, the flocculant solution concentration was 0.21%, the flocculant addition amount was 31.37 g/t, and the predicted target underflow concentration was 57.97%. The verification test was carried out under these parameters, with less than 2% error. Thus, the reliability of the model is high, providing an important basis for the determination of mine flocculation sedimentation parameters.