Medium Range Weather Forecasts, were used to study lightning in different regions of mainland China. The relationship between lightning and convective available potential energy (CAPE), precipitation (P), convective inhibition (CIN) and relative humidity (RH) was analyzed from the spatial and temporal distribution and quantitative relationship. The results show that lightning has a good correlation with CAPE, P and CAPE×P in time and space. An appropriately small CIN and a sufficiently large CAPE are most conducive to generating lightning; The higher the CAPE, the more lightning; The smaller the inhibition energy is, the more likely it is to convection and further generate lightning. However, CIN should not be too small, because too small CIN will lead to less lightning. A low CIN value is not sufficient for lightning to occur, and the relative humidity needs to be high. Lightning activity is concentrated in the environment where RH is 60%~90%. If RH continues to increase, lightning activity will decrease. Even in high CIN conditions, with certain moisture and CAPE conditions, there can be a lot of lightning.