In this paper,we have studied the effect of the lightning strike to tall towers ranging from 50 m to 300 m height on transient electric field at mesospheric altitudes.For subsequent lighting current wave with rise-time (RT) ranging from 0.2 μs to 2 μs,it is found that the presence of the tall tower tends to increase substantially the electric field peak values and their derivatives with more high frequency components due to transient process of lightning current wave in the tall tower.The less RT and taller towers result in a much stronger field peak.For example,the lightning current wave with a RT of 0.2 μs,striking a 300-tall-tower,produces the radiation field pulse with a magnitude about several times larger than that for strike to flat ground at 80 km altitude.However,with the increase of RT,the effect of strike to tall towers on the far field becomes less.