The invention discloses an alternating current transmission line iron tower which comprises a tower body and a cross arm at the top end of the tower body. The middle and the two ends of the lower side of the cross arm are each connected with a lightning-proof insulator. The lower ends of the lightning-proof insulators at the two ends are each connected with a side phase conductor. The lower end of the lightning-proof insulator in the middle is connected with a middle phase conductor. A compound fiber overhead ground wire is arranged on the waist of the tower body. The conductors are suspended on the lightning-proof insulators, so that the alternating current transmission line iron tower has the functions of suspension, insulation and lightning prevention at the same time. When ground lightning directly strikes the tower or the conductors, the lightning overvoltage will make the lightning-proof insulators move, impact energy is absorbed, the overvoltage is suppressed so as to protect the insulators against flashover, tripping of a transmission line is avoided, and power supply reliability is improved; the compound fiber overhead ground wire is located below the three phase conductors, so that the normal power communication function is achieved, the lightning overvoltage on the lightning-proof insulators can be decreased due to the coupling effect, the lightning-proof level is further improved, the lightning tripping frequency of the transmission line is effectively decreased, and the power supply reliability is improved.