The existence of the polymorphism brings many changes on the executable paths of the object-oriented program, which makes it difficult to test the internal communication of the system and the interaction between the objects. This paper analyzes the structure feature of the Java program and builds an inheritance tree using the technique of reflection in Java, which guarantees the accuracy of the analysis data. This paper proposes an algorithm to determine the uniqueness based on the full analysis of the Java polymorphic calling states and the Liskov substitution principle. And the algorithm uses the asynchronous mode of high concurrency to increase the efficiency. The result shows the algorithm can determine the uniqueness of polymorphism efficiently and accurately. It can play an important role in the Java program comprehension and the system maintenance.