Traditional research on railway track parameters is based on vehicle dynamics theory, neglecting the dynamic interaction between vehicles and track structures. As the operation speed of high-speed railways increases, the system response induced by track geometry becomes significantly stronger, and the relationship between track geometry and passenger comfort becomes more important. The limitations of traditional track research methods are becoming more evident, mainly in the following aspects: (1) inability to analyze wheel-rail dynamic safety indices and ride comfort indices when trains pass through curves; (2) inability to analyze and evaluate the matching of horizontal and vertical alignments and the mutual influence between successive alignments; (3) inability to separately consider the influence of different subgrade structures. Therefore, applying railway track system dynamics theory to study the reasonable selection of track alignment parameters, as well as evaluating and optimizing track design schemes, has become a more scientific approach. This chapter introduces the application of track system dynamics theory in the study of key horizontal and vertical alignment parameters of high-speed railway tracks, the matching of horizontal and vertical profile parameters, and the applicability of parameters for high-speed railway speed increases.