Abstract: The analytical expression of electromagnetic field which is generated by vertical and oblique channel is obtained by solving the Maxwell's equations. The spatial distribution laws of lightning electromagnetic field is analyzed base on analytical expressions. The results show that in model of vertical and oblique channel the impact of vertical electric and magnetic fields by observation height will decrease with the increasing of the horizontal distance. The peak value of horizontal electric field will increase with the increasing of observation point height in vertical channel model. But for horizontal electric field, the peak value will increase with the increasing of observation point height in vertical channel model, while in model of oblique channel when observation point is below discharge channel, the peak value will increase with the increasing of observation point height, when the observation point is above the discharge channel, the peak value will decrease with the increasing of observation point height.