Despite advancements in aviation technology, the occurrence of spin has not diminished, and this persistent threat to aviation safety continues to garner widespread attention. The primary focus of this research is to address the limitations of current aerodynamic coefficient decomposition techniques. To this end, a novel method is introduced, which builds upon the traditional Kalviste decomposing method. This method encompasses a detailed description of spin mode modifiers with varying characteristics and a mathematical model of spin in vector form. Furthermore, the study delves into the decomposition of motion and the structure of aerodynamic coefficients. A numerical example is provided to demonstrate the prediction of aircraft spin characteristics. To validate the effectiveness of this method, an analysis of the dynamic characteristics of aircraft spin is conducted based on differential equation theory. The simulation results indicate that the proposed motion decomposition method can accurately predict the spin characteristics of aircraft and align with authoritative standards, thereby validating its efficacy in this context.