Test case prioritization technique aims to improve test efficiency rate by sorting test cases according to some specific criteria. Requirements play an important role throughout software testing. This paper proposes a test case prioritization method based on requirement correlations. Prioritization of requirements is defined by the users and the developers. This technique focuses on requirements with detected faults after the last regression testing. By readjusting prioritization of fault-related requirements, it can optimize the order of test cases. Experimental results show that this technique exactly contributes to achieving high testing efficiency.