Abstract: Objectives With the growing demand for polar research and shipping, the design of polar ship hull lines has received increasing attention. To address this need, the study investigates the influence of bow geometric parameters on ice-clearing performance. Methods A numerical simulation model of ship interactions with level ice and broken ice is developed based on the circumferential crack method and the non-smooth discrete element method. Using this numerical model, towing test simulations are conducted. After that, a fully parametric modeling technique is applied to a U.S. Coast Guard heavy icebreaker as the parent ship to systematically explore the effects of various bow geometric parameters on the ice-clearing resistance of heavy icebreakers with straight stempost. Results The simulation results for the towing condition show an error of less than 10% compared to model tests, validating the numerical model. An increase in stem angle leads to a roughly nonlinear increase in ice-clearing resistance, while the effect of the waterline entrance angle is more complex and closely related to the form of the fore waterline. Describing the bow waterline form by its fullness within the first quarter breadth, the resistance initially decreases, then increases, and finally decreases again as the waterline transitions from straight to slightly convex and then to convex with increasing fullness. Furthermore, a coefficient k, comprehensively reflecting the influence of the stem angle and waterline shape, is introduced. As k increases, the ice-clearing resistance first slightly decreases and then gradually increases. Conclusions The developed analytical methodology for assessing ice-clearing capability offers a theoretical foundation and practical framework for the optimization of bow lines in polar vessel design.