A mathematical model describing fluid flow, heat transfer and pressure distribution inside a sloped-collector solar updraft tower power plant (SCSUTPP) is presented by assuming a steady compressible flow. Compared to conventional horizontal-collector solar updraft tower power plants (HCSUTPPs), the performance of SCSUTPP is comprehensively studied based on the mathematical model. The power outputs for SCSUTPP and HCSUTPP using the essential expression of driving force are respectively compared with those using the driving force expressions containing no integral, as proposed in literature. Results show that the expression containing no integral is accurate for HCSUCPP based on a compressible fluid model. The expression containing no integral is not accurate for predicting the driving force of SCSUTPP based on an incompressible fluid model when no variation of the atmospheric density with heights and no variation of difference of the atmospheric density and the density of the current inside the short SUT with heights are assumed. The gravitational effect has to be considered for predicting the SCSUTPP performance. The results show that the pressure potential and the power production of an SCSUCPP with a collector of 848 m height and a vertical SUT 123 m high lies between those for two HCSUCPPs respectively with vertical SUTs 547 m and 971 m high. This work lays a good foundation for accurate predication of potential power produced from SCSUTPP. (C) 2013 Elsevier Ltd. All rights reserved.