Purpose: This study examined the effects of simulation-based education for high-risk maternity on evaluating problem-solving process, self-leadership, critical thinking disposition, and selfefficacy of nursing students. Method: This study was a one-group pretest-postest test design with 81 junior nursing students as participants. Data were collected from September 4 to December 11, 2019, after students completed their simulation practice class. Students completed a survey on their problem-solving process, self-leadership, critical thinking disposition, and self-efficacy at the beginning and end of the class. Data were analyzed using descriptive statistics, paired t-test, and Pearson’s correlation coefficients using the SPSS WIN 21.0 program. Results: Students’ problem-solving process (t=-7.06, p<.001), self-leadership (t=-3.08, p=.003), critical thinking disposition (t=-2.12, p=.037), and self-efficacy (t=-6.01, p<.001) showed significant improvement after the simulation-based education for high-risk maternity. There was a positive relation between problem-solving process and self-leadership (r=.52, p<.001), critical thinking disposition (r=.39, p<.001), and self-efficacy (r=.53, p<.001). Conclusion: There is a need to supplement the limitations of clinical practice education by providing a simulation-based education environment similar to a hospital since the experience of clinical practice alone is not sufficient to improve students' knowledge and skills. Results of this study may be used as a basic data for efficiently performing simulation-based education on high-risk maternity.