The magnitude of lightning current is an important parameter for studying the distribution of lightning in a region. This paper uses the lightning monitoring data of the ADTD lightning positioning system of Henan Province from 2008 to 2017 to fit the characteristic function of the formula recommended by the protocol method, IEEE working group and CIGRE working group. The results show that there are differences in the probability distribution of positive and negative lightning current values in Henan. The formula recommended by the IEEE Working Group is used to fit the probability distribution of the accumulated magnitude of the lightning current in Henan Province. At the same time, the expression of the probability distribution function of the accumulated magnitude of the lightning current in Henan Province is obtained. It provides an indispensable technical reference for studying the characteristics of lightning in Henan Province and carrying out lightning protection and disaster reduction.