The conductance of trans‐polyacetylene is measured during oxidation using an interdigital microelectrode. The measurements obtained indicate a slight increase in the conductivity during initial exposure in air and then a decrease during oxidation, which is confirmed by the corresponding changes in the infrared absorption spectra. The logarithm of conductivity is inversely proportional to the oxidation time. A proposed model which is derived from Kivelson’s theory predicts the behavior of conductivity as a function of time during oxidation. The experimental data of conductivity is in agreement with the calculated data using this model. The temperature dependence of the conductivity at certain stages also supports the theory that the electrical transport mainly occurs through intersoliton electron hopping. Thus, the electrical transport mechanism during oxidation is clarified.