Theoretical analysis and a large number of experiments have proved that plasma components do not satisfy Boltzmann–Gibbs statistics and can be well described by nonextensive statistical mechanics, while sheath potential coefficients in plasma with nonextensive distribution are not investigated deeply and comprehensively. Here, we investigate the ion sheath formed around a nonextensive single electric probe in plasma described by nonextensive statistical mechanics, and find that the sheath potential coefficient is related to the electron nonextensive parameter, besides the extensive limit the results return to the case of the Boltzmann–Gibbs statistical framework. The sheath potential coefficient presents different dependences on the electron nonextensive parameters in different regions. We also have calculated the corresponding method error and evaluated with a set of real experiment data, and found that the error is as high as 83.91% indicating that the effect of nonextensive parameters should be considered in the actual measurement.