To utilize heat from round shaped heat sources or heat sinks effectively, a segmented annular thermoelectric generator was proposed. Each leg is composed of two materials with different optimum operating temperatures jointed in series. Based upon a developed theoretical model, the influences of annular shape parameter, height ratios of high temperature segment to leg in p- and n-type legs, temperature ratio and load ratio on the performance of segmented annular thermoelectric generator were studied. A finite element method was adopted to consider the Thomson effect and temperature-dependence of materials. Performance comparisons with simply non-segmented annular thermoelectric generators were conducted. For application security, the interface temperatures were analyzed. Results show that compared to a simply non-segmented annular thermoelectric generator, the superiority of segmented annular thermoelectric generator becomes visible with rising temperature ratio. As the annular shape parameter increases, the power rises firstly and then declines, and the optimal annular shape parameter is around 1.0, but not strictly equal to 1.0. Besides, the optimal ranges of height ratios in p- and n-type legs for higher performance are identified. The current study demonstrates the potential of segmented annular thermoelectric generator from the perspectives of performance and practicability. (C) 2018 Elsevier Ltd. All rights reserved.