Based on the daily sounding data of Zhangqiu Sounding Station between June and August from 2006 to 2015, the 6 environmental parameters, such as K index, lifting index, and convective stability index, are calculated. The correlations between a single environmental parameter and lightning activities as well as correlations between combined environmental parameters and lightning activities are studied. The results are as follows. 1) A single environmental parameter within a range of values can be used as an indicator of lightning activities and stronger lightning activities are more likely to be predicted based on the atmospheric instability. 2) Combined environmental parameters can reflect the characteristics of lightning activities to some extent. With the increase of the number of physical parameters reaching critical values in the unstable state, the probability of lightning activities increases and the forecasting skills are better than that using a single parameter. 3) Regression estimation of event probability method is used to establish an equation of lightning probability forecast, which passes the significance test at 0.01 level, and the threat score of the probability forecast reaches 78%. The method provides reference for the lightning potential forecast.