Abstract: To explore the cause of airflow velocity reading disorder and accurately select the surveying location and methods，the numerical simulation was adopted to selecting five typical situations that are disturbed by the pedestrian to simulate the airflow field affected by the pedestrian.Then the distributive characteristic of airflow velocity was revealed in different situation，and the range of the pedestrian's influence on the airflow velocity measuring was analyzed.Among them，when one person stands on the side of roadway，the oscillating area the behind the wind to the left has full development，and the velocity difference is still to be 0.76 m/s at the monitoring line 20 m behind the people.At situation 5，the oscillation areas behind three people are balanced out with each other，and the velocity difference is only to be 0.04 m/s at the monitoring line 20 m behind the people.The conclusions showed that due to the person's existence，there will be a velocity disorder region behind the person.The velocity will be slow down behind person but it will be increased at his side.The oscillation will be attenuated slowly if let it grow freely.The simulation result has certain reference and practical application value for measuring airflow velocity at underground.

Key words: Ventilation, Numerical simulation, Airflow velocity in roadway