In the paper, based on fluid dynamics and self-organization theory, dynamical characteristics of columnar joints in basalt are studied and all parameters of dynamical equations are calculated according to the mean chemical compositions of basalt in Zhenhai, Fujian Province. We have found the functional relation between the thickness and section diameter of columnar joints; moreover, the result of digital simulation of dynamical equations is consistent with the local geological conclusion. Finally, we have also probed into the genesis of columnar joints and divided the process of the formation of columnar joints into two stages: (1) thermo-dissipative-convection stage and (2) cooling-contraction stage.