The purpose of this study is to investigate the effect of 12-week resistance exercise on physical strength, balance ability, cognitive function, and depression in elderly men with mild cognitive impairment (MCI). To conduct the study, MCI was first selected using a mini-mental state examination(MMSE) test. In addition, 20 elderly men aged 60-70 were recruited and randomly divided into an exercise group and a control group. The exercise group conducted resistance exercises using pilates three times a week for 12 weeks, 60 minutes each time, and a total of two body composition, bug balance ability, cognitive function, and depression tests were conducted to compare the effects with the pre and post control groups. As a result, there were significant differences between groups in body fat percentage, agility, upper limb flexibility, endurance, and balance ability of the elderly in MCI. In addition, MMSE total score was improved and depression level decreased, confirming the effect of resistance training on preventing dementia. Therefore, the resistance exercise conducted in this study is effective in reducing obesity and depression, which are risk factors for dementia, and the increase in muscle strength and balance function in the exercise group can prevent sarcopenia, which is the cause of dementia.