The invention discloses a radio interference computing method for computing radio interference to an alternating-current high-voltage multi-loop electric transmission line. The radio interference computing method includes: dividing a super-high-voltage and an extra-high-voltage multi-loop electric transmission line into a first line group and a second line group; computing radio interference values of the first line group by a CISPR (International Special Committee on Radio Interference) empirical equation method and a CISPR excitation function method; converting the radio interference value computed by the CISPR excitation function method into a value in good weather by the aid of a meteorological correction factor, and comparing the converted value with the result computed by the CISPR empirical equation method to obtain an excitation function correction factor; using CISPR excitation functions to establish a radio interference computation model, computing excitation functions of the first line group and the second line group under the condition of heavy rain respectively, and correcting the excitation function of the first line group under the condition of heavy rain according to the excitation function correction factor; computing the total radio interference value of the alternating-current high-voltage multi-loop electric transmission line under the condition of heavy rain according to the above data, and correcting the total radio inference value through the meteorological correction factor to obtain the total radio interference value of the alternating-current high-voltage multi-loop electric transmission line in good weather.