Abstract: Test case prioritization (TCP), as one of the regression testing techniques, can greatly improve the efficiency of regression testing. Considering that most of the existing TCP techniques neglect to use software structure information, this paper proposes a new regression test case prioritization technique based on bug propagation network. It uses weighted class dependency network (WCDN) to represent the topological structure of a piece of software at the class level of granularity, and then analyzes the propagation process of bugs on WCDN to construct the BPN. When performing regression test case prioritization, it first locates the modified classes and the potential impacted classes. Then it calculates the test influence for each class. Finally, the test importance for each test case, the sum of the test importance of all classes it covered, is calculated as the criteria to prioritize regression test cases. Case studies on several real world open-source software systems show that, compared with other test case prioritization techniques, the proposed technique has better effectiveness and comparable stability.