The maneuvering motions of ice breakers are the determining factor of the maneuverability. The ice force (moment) is calculated by using a semi-analytic icebreaking force decomposition model based on the mathematical model of maneuvering motion. The corresponding influences of parameters, such as ice thickness, ice strength, main engine power and rudder angle, on the maneuvering motion are also analyzed. Then the quantitative law of the combined effects of parameters is obtained based on the Least Square Support Vector Regression (LS-SVR) method for the intelligent prediction of the maneuverability of the icebreakers. The navigation trajectory can be predicted in real-time under the current control instructions and sea ice information by using this model, which can be used to assess the effectiveness of the avoidance strategy in advance and to improve the navigation safety.