A software function verification system and a software function verification method are provided. The system includes a first database, a document acquisition device, and a function verification device. The function verification device analyzes a first-party document according to a machine learning technology to generate a plurality of first-party technology points and converts the first-party technology points into a first-party decision table. The function verification device analyzes a second-party document to generate a plurality of second-party technology points and converts the second-party technology points into a second-party decision table. The function verification device respectively converts the first-party decision table and the second-party decision table into a first-party tree structure and a second-party tree structure and compares the first-party tree structure and the second-party tree structure to determine the degree of functional differences between the first-party document and the second-party document.