The purpose of this study was to identify factors affecting the Patient Safety Management Activity (PSMA) of nursing students according to levels of PSMA based on the Theory of Planned Behavior (TPB). Methods: A descriptive study was used. The participants were 135 nursing students from universities in Korea. Data were collected with self-reported questionnaires through online survey. The questionnaire consisted of PSMA scale and modified version of the TBP-based questionnaire. Data were analyzed using multiple linear regression and quantile regression. Results: The average score of PSMA was 4.09±0.44 out of 5 points. In the multiple linear regression, patient safety education, subjective norm, perceived behavioral control and intention were significant factors. In the quantile regression, place of clinical practice (in 75%), patient safety education (in 50% and 90%), subjective norm (in 75%), perceived behavioral control (in 50% and 75%) and intention (in 50%) were significant factors. Conclusion: We confirmed the dynamic influences of all factors according to the levels of PSMA. It is proposed that the affecting factors according to the levels of PSMA should be considered in designing effective programs to enhance PSMA among nursing students.