The 3D Laser Doppler Velocimeter (LDV) system was used to study the fire whirlwind flow field induced. The fire whirlwind characteristics parameters, induding radial velocity, tangent velocity and axial velocity, were obtained from the observation and masurement of the fire whirlwind by the infrared thermography and the themocouple. This experiment deepened the understanding of the mechanics of fire whirlwind entrainment and laid a good foundation for experiment study of fire whirlwind entrainment in the next step.