Abstract: The velocity of flame propagation has a great influence on the peak pressure caused by gas explosion.The influence of self-development, tube and obstacle on flame velocity were considered on the basis of existing data.In analyzing the acceleration mechanism of flame propagation in tubes, turbulence factors were introduced to measure the turbulence effect of deflagration flame propagation and a simplified calculation method on the maximum velocity of flame propagation was obtained.Compared with test data, the simplified method agrees well with the experimental results within the scope of application, and the accuracy of turbulence factors were proved in calculation.The determination of turbulence factors makes the measurement of flame maximum velocity more convenient.