Abstract: Embodiments of the present application provide a preparation method of a silver nanowire with a circular cross section, which relates to the field of nanometre material technologies. In the embodiments of the present application, by heating a mixed solution of the silver nanowire with the pentagonal cross section, the reducing sugar, the oxygen reducing agent and the water, an unstable silver nanowire with the pentagonal cross section are transformed into a stable silver nanowire with the circular cross section, and then the risk that a transparent conductive films based on the silver nanowires lose conductivity is avoided. In addition, in terms of an optical performance testing, compared to conductive films based on the silver nanowires with the pentagonal cross section, conductive films based on the silver nanowires with the circular cross section have significantly reduced a haze.