Abstract: The influence of milling parameters on milling force during milling 7075 aluminum alloy grooves with ball end mills was studied using the orthogonal experimental method. The influence degree of each milling parameter on the three-directional milling force was investigated through range analysis and variance analysis. The influence law of milling parameters on milling force was further studied by the single-factor experimental method and the influence mechanism of milling parameters on milling forces was discussed. The empirical formula of the three-directional milling force for milling 7075 aluminum alloy grooves with ball end mills was established, and the reliability of the milling force empirical formula was tested by regression analysis. The experimental results show that the ranking of the influence degree of each milling parameter on the three-directional milling force when milling 7075 aluminum alloy grooves with ball end mills is the feed per tooth f_z > milling depth a_p > milling speed v_c. By increasing a_p, the milling efficiency is improved and the dimensional accuracy of the groove width is more contributed. The milling force empirical formula has a high fitting degree and strong significance, and it can relatively accurately predict the three-directional milling force within the parameter range of this experimental system.