Abstract: To address the problem of low coverage and efficiency of the test cases generated by the existing industrial control protocol fuzzy test framework, we propose a test case generation method based on feature matrix. First, through an analysis of the protocol agreement to extract protocol features and constraint rules, the protocol feature matrix is constructed by the Cartesian product of the property values of each protocol feature. Then, the targeted structural variation strategy is designed to act on the feature matrix, while the constraint rules are used to reduce the redundancy of test cases and obtain a high-quality combination test case set. Finally, the test case generation algorithm based on the feature matrix is proposed. A comparison with the Peach framework shows that the method can effectively improve the coverage of test cases and test execution efficiency. Moreover, the method can detect vulnerabilities.