The invention discloses a method suitable for calculating transmission line pole tower grounding body lightning impulse characteristics. By means of the method, formulas for calculating all basic parameters of a grounding body under the action of a lightning current impulse are determined on the basis of the circuit theory; nonlinear spark discharge is presented through a circuit parameter dynamic change calculation model on the basis of existing formulas and through the combination with the soil spark discharge theory; the calculation thought and method are put forward, and therefore the nonlinear relation between the current of each small section of the grounding conductor in the spark discharge process and the ground resistance, namely, the conductance, of the small section of the grounding conductor in the spark discharge process can be obtained, and the ground resistance is changed instantly according to the current of a branch circuit, and the inductance effect, the spark effect and the lightning current time-varying characteristics are taken into consideration at the same time; meanwhile, the calculation process is simple and visual, workloads are small, parameters can be flexibly changed, and a rapid means is provided for correctly researching the pole tower grounding body lightning impulse characteristics.