The transition characteristics of blunt cone boundary layers under the flight and ground conditions were firstly compared. Then the e^N method based on the linear stability theory was used to predict the boundary layer transition of blunt cone in the cases of ground and flight tests. Finally the effects of ratio of wall temperature to total temperature on the stability and transition of boundary layer of high speed blunt cone were investigated. The results showed that the boundary layer transition on the centerline of windward face and the side face happened earlier than that between them under the condition of lower ratio of wall temperature to total temperature， and the transition morphology is similar to that in flight cases. However， the boundary layer transition on the windward face occurred later than that on the leeward face in higher ratio of wall temperature to total temperature， and the transition morphology is similar to that of in ground cases. The ratio of wall temperature to total temperature is an important factor which results in the discrepancy of boundary layer transition in flight and ground cases of high speed blunt cone.