The expressions containing no integral and considering the gravitational effect for predicting the pressure potential of a sloped-collector solar updraft tower power plant (SCSUTPP) under various conditions are developed based on a compressible fluid model. Based on the mathematical model of a sloped collector presented by Zhou et al. (2013) [8] and the expressions of the pressure potential developed, the performance of SCSUTPP is comprehensively studied under various conditions by assuming a steady compressible flow. The pressure potential for the vertical tower estimated using the relative humidity of the air based on the temperature at the tower inlet due to higher temperature is shown to be over-predictive, as compared to that based on the temperature at the collector inlet, when the effect of the collector height on the pressure potential has not been considered. The results for SCSUTPP using the pressure potential expression for dry air are basically shown to be in good agreement with those using the essential expression. The pressure potential and power output are shown to decrease with the increase in the same relative humidity of the air inside and outside the SCSUTPP. This variation trend is opposite to that obtained for dry air outside the SCSUTPP. The pressure potential and power output are found to gradually increase with the increase in the ambient pressure, the collector height, or the tower height, or the decrease of the ambient temperature. The increase in the temperature due to the latent heat released from the potential vapor condensation is large enough to stop the vapor to continue condensation. This work lays a good foundation for the predication of the potential power production from SCSUTPP. (C) 2014 Elsevier Ltd. All rights reserved.