By measuring the EEG signals of subjects completing work tasks in different postures (sitting, standing and walking slowly on the treadmill), the spectrum analysis was done and compared after removing the artifacts. It is found that there is little difference in alpha band of EEG between standing and sitting posture, and walking posture requires higher energy in some channels than standing and sitting posture. Therefore, in our daily work, we can adopt the way of standing posture to improve the health problems caused by sedentary while not affecting our work. When using walking posture or more intense exercise, it is necessary to reduce the difficulty of work tasks.