Abstract: In this papor throe-dimonsional analysis of an intonsely developed cyclone in Northeastorn China in Dec. 10 to 20 1957 is presontod. It is found that at all levels in the center of this cyclono there is ascending notion daring the development. Within the cold dome, there is also ascending motion at all levels. Accompanying development of this cyclone, the ascending motion, divergence and convergence over the center are intensifing, and the level of non-divergence subsides and tends tojvards symmetry.