Water vapor condition is an essential meteorological element for lightning activity. Using the monitored cloudground lightning data from lightning detection system in Hebei Province and relative humidity data in NCEP/NCAR data in 2013, the lightning characteristics and response relationship between lightning activity and vertical structural characteristics of atmospheric relative humidity are analyzed. The results show that (1) The time distribution of lightning at Zhangjiakou was basically consistent with that of Hebei Province, and lightning activity was the strongest in summer and uneven in monthly change;there was a daily summit appearing from 17:00 to 18:00 and a valley from 01:00 to 09:00. (2) There was obvious response relationship between lightning activity and relative humidity vertical structure: the relative humidity was not high at about 850 hPa, but more humid at about 700 hPa, then became dry at upper layers; the relative humidity increased with height below 700 hPa and deceased above 600 to 700 hPa. (3) When lightning occurred, the local characteristics of atmospheric environmental conditions of relative humidity in Zhangjiakou include: relative humidity was about 40%～60% at about 850 hPa; 60%～80% between 600 and 700 hPa, and decreased to about 20%～40% between 200 to 400 hPa.