Objective The aim of this study was to systematically review the efficacy and safety of exercise in patients with amyotrophic lateral sclerosis (ALS). Design Randomized controlled trials of exercises for ALS were searched in PubMed, EMBASE, Web of Science, Cochrane Library, China Biology Medicine database, China National Knowledge Internet, VIP database, and Wanfang database. The primary outcomes were functional ability, pulmonary function, and quality of life. The secondary outcomes were muscle strength, fatigue and adverse events. Meta-analysis was performed using the RevMan Version 5.3 software. Results Seven randomized controlled trials including 322 patients with ALS met the inclusion criteria. Meta-analysis showed that the functional scores at long-term (standardized means difference, 0.47; 95% confidence interval, 0.08-0.86;P= 0.02) and forced vital capacity percentage predicted (mean difference, 1.71; 95% confidence interval, 0.10-3.31;P= 0.04) of patients with ALS in the exercise group were significantly higher than those in the group of no exercise or usual care. No significant difference was observed in muscle strength and quality of life. Endurance or aerobic exercise improved the functional scores of patients with ALS (standardized means difference, 0.36; 95% confidence interval, 0.04-0.68;P= 0.03). Exercise did not aggravate fatigue or result in adverse event. Conclusion Exercise can significantly improve the functional ability and pulmonary function of patients with ALS safely.