Aiming at the current problems of high cost， low simulation accuracy and difficulty in ensuring real-time performance of tunnel fire smoke velocity measurement， a method for estimating smoke velocity of tunnel fire based on particle filtering was proposed. Firstly， the relevant system state equation and observation equation were established， and then the observation values were obtained by using the real-time sensor data. Finally， the real-time estimation of smoke velocity was realized by using the particle filtering algorithm. Experimental results show that the response time of the proposed method can reach the millisecond level， which can basically meet the real-time requirements； and the Mean Absolute Error （MAE） of smoke velocity can basically be controlled within 20% of the true value with high simulation estimation accuracy. The proposed method can provide useful key information for fire rescue and evacuation， and provide theoretical basis for smoke extraction system and fire planning strategy.