With the ever-increasing expansion in scale of the power system， the secondary development of stability devices is facing enormous pressure. This paper analyzes the characteristics of the control strategy and proposes a finite-state machine model for strategy table search and match of the standardized stability control device. The control strategy is divided into 6 categories， including the operation mode set， current operation mode， fault state set， control set， transition of operation mode， and strategy table search and match. By building the one-to-one mapping between the 6 elements of control strategy and mealy finite-state machine to form the unified mathematical mode， the standardized expression mode is characterized by clear physical concept and logical relationship， simple expression and good agreement with the actual dynamic process. This will decouple the strategy table from search-and-match， while simplifying the process of software development and testing. Engineering tests show that the state machine model has improved the overall efficiency of the stability control project.