When the positive pressure explosion-proof robot is in ventilation, if the air is filled into the cavity with a constant pressure, a stable flow field will be formed in the cavity. There is a stagnation zone of airflow in the corner position, which will cause the accumulation of explosive gas. In order to solve this problem, the ventilation method of periodic pulse intake is adopted on the basis of the existing robot positive pressure explosion-proof structure. The variation of explosive gases concentration in the robot cavity with time under constant pressure and pulse pressure with different periods and amplitudes is compared. According to the simulation and experimental results, it is found that the pulse intake is beneficial to the ventilation of the corner position. The period and amplitude of the pulse intake has an effect on the ventilation efficiency, when the period is the same, the greater the amplitude of the pulse intake, the higher the ventilation efficiency; when the amplitude is the same, the smaller the period of the pulse intake, the higher the ventilation efficiency.