The present invention provides a field authentication method for a pollution area distribution map. The method comprises the following steps: (1) selecting an authentication area; (2) collecting field data of the authentication area; (3) using a frequency method to account a prevailing wind direction of the authentication area; (4) determining an impact radius of a pollution source and a pollution level of the pollution source; (5) drawing pollution distribution of the pollution source in the prevailing wind direction; (6) calculating equivalent salt and non-soluble deposit densities of field insulators, and converting to a pollution level; (7) drawing pollution distribution of the field insulators; (8) combining the pollution distribution of the pollution source with the pollution distribution of the insulators to acquire pollution distribution of the authentication area; and (9) performing comparative analysis between the pollution distribution of the authentication area and the pollution area distribution map, and authenticating accuracy of the pollution area distribution map. The present invention provides a method for authenticating the accuracy of the pollution area distribution map by using field weather data, field pollution source data, pollution online monitoring data, and artificial field test data, so that an effective guiding basis is provided for carrying out of pollution prevention of a transmission line.