The clinical features and electromyography features of anal sphincter in patients with multiple system atrophy were analyzed, and the value of electromyography of anal sphincter in early diagnosis of multiple system atrophy was discussed. A retrospective analysis was conducted on 26 patients with complete information who were hospitalized for multiple system atrophy from January 2019 to July 2022 at the Aerospace Center Hospital. The patients general information, activities of daily living score, and external anal sphincter electromyography results were collected. The patients were grouped based on whether there were satellite potential, urinary and bowel disorders, or orthostatic hypotension, and the age, duration of disease, activities of daily living score, and external anal sphincter electromyography results were compared between the groups. The correlation between the motor unit potentials average duration of external anal sphincter electromyography, disease duration, and activities of daily living score were analyzed. The most common symptoms in 26 multiple system atrophy patients are urinary and bowel disorders, gait disturbance, and sleep disorders, while the most common signs are muscle tension disorders, orthostatic hypotension, and ataxia. The mean duration of motor unit action potential in 26 patients is 11.6 ms (range 10.1 ms to 14.5 ms), the mean amplitude is 876.5 μV (range 740.8 μV to 1 135.8 μV), and the percentage of multiphase wave is 27.4% (range 13.3% to 53.6%). The group with satellite potential has a longer average duration, a higher percentage of multiphasic waves, and lower activities of daily living scores (P <0.05). The group with orthostatic hypotension has lower activities of daily living scores (P <0.05). The disease duration of multiple system atrophy patients is significantly negatively correlated with activities of daily living scores (r = -0.695, P = 0.000), while there is no significant correlation between disease duration and the average duration of motor unit potentials, or between activities of daily living score and the average duration of motor unit potentials. The longer the disease duration in multiple system atrophy patients, the more severe the disease becomes. Patients with satellite potential or orthostatic hypotension have more severe disease conditions. External anal sphincter electromyography is advantageous in the early diagnosis of multiple system atrophy patients without urinary and bowel disorders.