Abstract: The performance of optics instrument was more and more affected by aerosols while it was flying with the aircrafts in the atmosphere.It has a quite important significance on the evaluation of optics working efficiency on the aircrafts that the particulates moved and pooled in complex vortex flow field.While the estimate of particulates in the atmosphere coupled with complex vortex field is always one of the most important problems in the research of aircraft envi-ronment.The complexity of aerodynamics and the diversity of atmosphere are always the main factors to restrict both the development of experiments and the foundation of the numerical mod-el.The distributing and velocity characteristic of particulate in complex vortex flow field was re-searched for the first time by advanced PIV technology in the low speed wind tunnel.Through the measurement to the vortex after the rudder,the instantaneous picture of distributing particu-late in the flow field was captured by PIV technology.The laser light scaning the flow field and exposure synchronization were used in the experiment.The instantaneous regularities of distribu-tion of particulate in complex vortex flow field was finally acquired through the image post pro-cessing technology,cross-correlation processing and gray scale calculating on original particulate picture.The result shows that by the principle of Mie scattering through the particulates in the laser light,the picture about the instantaneous complex vortex and particulate distribution can be captured by CCD camera,and by this it solved the limitation that traditional measurement equip-ments can not get the information of distribution of particulate in complex vortex flow in real time. In the flow field dominated by vortex,the particulate in atmosphere was pulled by centrifugal force,moved to balance and finally pooled to a loop around the core of the vortex.In this area,the coeffi-cient of particulate density is much larger than it in the free flow,and in the center of the loop,there is few particulate in the core of the vortex.