An exceptional heavy snowstorm occurred in the eastern part of Heilongjiang Province on 4-5 March 2007.The dynamical structure features are analyzed using the Doppler weather radar data in Mudanjiang.The result shows that the upper-lower jet streams, wind shear and cold-warm advection are characteristic during the process of snowstorm.The mesoscale convergence shear line and the position-change of southwest jet streams are caused by the warm south airflow and the cold northeast air current, which have important indicative significances in the process of snowstorm evolution.The radar reflectivity factor is between 15 and 27 dBZ, and the echo area is wide with the echo top of about 6 km.The cold-warm advection is obvious and the radial velocity is large.The phenomena of bull's eye squall and velocity ambiguity can be a starting point in forecasting of this kind of snowstorm.