This paper evaluates the benefits of meditation in regard to emotional intelligence (EI), perceived stress and negative mental health with cross-sectional and experimental studies. It first studied 351 full-time working adults with different amounts of experience in meditation for these factors in order to test the hypothesis that their differences in them were based on differences in meditation experience, and found that those participants with greater meditation experience exhibited higher EI, and less perceived stress and negative mental health than those who had less or none. It then randomly divided 20 graduate students with no previous experience of meditation into a mindfulness meditation group (n = 10) and a control group (n = 10), and measured them for the same variable pre-treatment and post-treatment to test the hypothesis that meditation training improves people's state, and found that those who completed the mindfulness meditation training demonstrated significant improvements compared to the control group.