Abstract: To study the vertical distribution characteristics of CH₄ within the troposphere in autumn in Shijiazhuang, the King Air 350 aircraft with Picarro greenhouse gas online observer and meteorological observation equipment were used to detect CH₄ concentrations over Shijiazhuang (600-5500 m) in September, 2018.A total of seven flights were made during the survey period, and seven CH₄ concentration profiles were obtained.The results show that the average concentration of CH₄ near the surface layer (below 1000 m) over Shijiazhuang is positively correlated with that at Shangdianzi station during the same period (r=0.81, P < 0.03).During the detection period, the minimum CH₄ concentration of the seven profiles is 1898×10^-9, the maximum is 2219×10^-9, and the average concentration is 1981×10^-9.The seven profiles obtained by observations are all consistent.The concentration above 2000 m increases first and then decreases with height.The backward trajectory mode-HYSPLIT model is used to analyze the main air transport paths at different altitudes over Shijiazhuang during the detection period.The transport pathways at 600 m are shorter, and the concentration of CH₄ is greatly influenced by local emissions.At 3000 m, the air mass with higher CH₄ concentration may be transported over Shijiazhuang by the west-southwest path.The air mass transport at 5000 m has little influence on CH₄ concentration.The CH₄ concentration at this level is relatively stable and insensitive to the change of transport path.