Background: Too many students persevere in relying upon one (sometimes suboptimal) strategy for solving a wide range of problems, even when they know more efficient strategies. Although many studies have mentioned such phenomena, few studies have examined how emotional factors could affect this type of inflexible perseverance in strategy use. Aims: To examine whether mathematics anxiety could affect students' inflexible perseverance in strategy use and whether this effect could be mediated by cognitive reflection, which is the ability to engage in deliberate reasoning. Sample and method: In Study 1, 164 undergraduate students' (18-22 years) mathematics anxiety, cognitive reflection, and performance in overcoming inflexible perseverance were measured by a questionnaire battery. Structural equation models were used to examine the correlations between these variables. In Study 2, 98 undergraduate freshmen (17-18 years) were assigned to two groups, where one group's mathematics anxiety was temporarily induced by task instructions, while the other group served as a control group. Cognitive reflection and inflexible perseverance of the two groups were compared. Results: Study 1 showed that mathematics anxiety was negatively correlated with students' performance on overcoming inflexible perseverance, while cognitive reflection mediated such an effect. Study 2 showed that compared to the control group, the experimental group showed lower cognitive reflection, which led to lower performance in overcoming inflexible perseverance. Conclusions: Mathematics anxiety was showed to impair students' ability to engage in deliberate reasoning and was associated with inflexible use of strategies. Alleviating students' mathematics anxiety should be considered when promoting students' strategic flexibility.