Objective To investigate the effect of resistance training intervention on the middle-aged and elderly patients with mild cognitive impairment (MCI). Methods A total of 40 middle-aged [(55±3) years old] and 40 elderly [(66±4) years old] male MCI patients from Dalian Community Health Service Center were selected and randomly divided into middle-aged control (MC) group and middle-aged intervention (MI) group , old control (OC) group and old intervention (OI) group. MC and OC group received routine health education, MI and OI group received resistance training for 24 weeks. Changes were measured in cognitive function, body shape, hormone levels and muscle strength of subjects. SPSS statistics 19.0 was used for statistical analysis. Data comparison between two groups was perfomed using t test or χ² test depending on data type. Results After 24-week of exercise intervention, compared with MC group, Montreal Cognitive Assessment (MoCA) score in MI group was significantly increased at T₂ stage (P<0.05), MoCA score in OI group was significantly higher than that in OC group at T₂ stage (P<0.05); compared with MC group, the body height, body mass and chest circumference of MI group increased slightly, and the waist circumference and hip circumference decreased slightly, but the difference was not statistically significant, and OI group showed the same trend compared with OC group; compared with MC group, the serum T and GH contents in MI group showed an increasing trend, while the serum C content showed a decreasing trend, and the serum T and C contents were significantly different at T₂ stage (P<0.05). Compared with OC group, OI group showed the same changing trend, and the improvement effect was better than that in MI group. Compared with MC group, muscle strength (grip strength) in MI group was significantly increased at T₂ stage (P<0.05), muscle strength (grip strength) in OI group was significantly higher than that in OC group at T₂ stage (P<0.05), and the improvement effect was better than that in MI group. Conclusion A 24-week resistance training can effectively improve the cognitive function of the middle-aged and elderly MCI patients, and the intervention effects are affected by multiply factors. It exerts a positive effect on hormone levels with a better effect in the OI group. However, the improvement effects on weight, height and body circumferences are not significant. It can effectively increase the muscle strength as represented by grip strength, and the increase is greater in OI group.