Low grade thermal energy powered desiccant wheel cooling system is an alternative solution to conventional electrical vapor compression system. Two-stage desiccant wheel cooling system is a newly developed configuration which can be driven by 50-90°C heat source. In this paper, two-stage system performance in terms of cooling power and thermal COP is investigated under different temperatures for different stages. Mathematical model describing the coupled heat and mass transfer in two-stage desiccant cooling system is adopted to predict the performance. Also, a new calculation mode is proposed to analyze thermal COP of the system with respect to the same cooling power however different regeneration temperatures. It is found that for the sustainable energy utilization, two-stage desiccant cooling system should operate under the condition of different regeneration temperatures, and the first stage should have higher temperature.