The super giant slalom (Super-G) is a speed event in alpine skiing, in which the skier trajectory has a significant influence on the athletes’ performances. It is a challenging task to determine an for the skiers along the entire course because of the complexity and difficulty in the convergence of the optimization model. In this study, a model for alpine skiers competing in the Super-G is established based on the theory, in which the objective is to minimize the runtime between the starting point and the finish line. The original problem is converted into a multi-phase nonlinear problem solved with a , and the trajectory parameters are optimized to discover the time-. Using carried out by the MATLAB optimization toolbox, the is obtained under several equality and inequality constraints. Simulation results reveal the effectiveness and rationality of the model. A test is carried out to show that our code works properly. In addition, several practical proposals are provided to help alpine skiers improve their training and skiing performance.