Based on the particle concentration, descending dust, satellite remote observati on，the aerosol extinction coefficient derived from Lidar observational data and physical quantity of sanddust weather process affecting Dalian, the character istic and dynamical mechanism of sanddusts invading Dalian were analyzed. The results show that the concentration of inhalational and total suspending particl es was increased remarkably and the descending dusts added in sanddusts. It transported at a level below 4 kilometers in Dalian, mostly located between 1 a nd 3 kilometers with the maximal aerosol extinction coefficient over 2.0km-1 . It exceeds 0.5km-1 near the ground and may be 1.3km-1 in the cas e of strong process. The precondition was that there were sanddust transportat ions of westwind or northwestwind jet streams, the glide streams in the rear of the front near Dalian contributed mainly to the rising of sanddusts concentration near the ground. The stronger the glide streams moved, the heavie r the pollution induced by sanddusts near the ground.