Based on the lifting design method of the axial flow hydraulic turbine and axial-flow pump impeller, an air turbine design method considering the optimal turbine pressure drop ratio for the solar chimney power plant was presented in this paper. Numerical simulations for the Spanish prototype system incorporating the turbine impeller were conducted to investigate the feasibility of the present turbine design method on the improvement of the system output performance. Furthermore, the influence of the solar radiation on the turbine performance was investigated. The results indicates that the turbine performance can be improved by using the proposed design method. The maximum turbine power output is 53.49 kW, 30.46% higher than that of the Spanish prototype and the turbine is less sensitive to rotational speed. In addition, the turbine high-performance rotational speed range is larger under higher solar radiation. (c) 2021 Elsevier Ltd. All rights reserved.