This study aimed to investigate the effects of simulation-Based Education on nursing students' nunchi, communication skills and clinical reasoning ability. For the study, an experimental study with a one group pre-post design was used. The participants were 48, 4-years nursing students from S University in G-city, and participated in the 'Simulation-Based Education' course for 12 weeks from August to October 2022. parid t-test using SPSS program. Result, Nunchi(t=3.29, p=.003), Communication skills(t=2.51, p=.018) and Clinical reasoning ability (t=-4.98, p<.001) of nursing students significantly improved after application of simulation-based Education. In addition, the correlation between nunchi, communication skills, and clinical reasoning ability shows that clinical reasoning ability has a strong positive correlation with Nunchi(r=.644, p<.001) and communication ability (r=.629, p<.001). A relationship appeared. Additionally, the factor accounted for 41.9% of the variance in Clinical reasoning ability. Therefore, it is necessary to develop various clinical nursing scenarios of simulation-based training education to nursing subjects to improve clinical reasoning capabilities for nursing students'. It is believed that the period of education should be considered before clinical practice.