During hypersonic flight in the terrestrial space, the heat flux loaded by some certain locations of vehicles, such as nose cone and combustion chamber, can reach very high values. Transpiration cooling has been recognized as one of the most effective technologies of heat dissipation to protect the vehicles from the very high heat flux. This paper presents an experimental investigation on transpiration cooling of the wedge shaped nose cone with an unequal thickness porous wall using liquid water as coolant. The experiments were performed in the heated gas wind tunnel at the University of Science and Technology of China (USTC), the surface temperature of the nose cone sample was measured by an infrared thermal imaging system, the pressure and temperature in coolant chamber were measured by a series of the transducers connected with a PC, to detect transpiration cooling effect and the driving force of the liquid water at different mainstream temperatures, Reynolds numbers and the coolant injection ratios. The experimental data indicated that the design of the unequal thickness walled nose cone is effective to solve the key issue of cooling stagnation point, there is an optimal coolant injection ratio, at which the driving force for the liquid transport through pores can achieve the minimum, and the average cooling effectiveness over total transpiration area is still at a relatively high level. (C) 2014 Elsevier Ltd. All rights reserved.