The propagation mechanism of detonation wave procreant in mixed gas is analyzed. The basic relation between the parameters of the detonation wave in propagation process is established. At the different pressure ratios, the detonation wave characteristic parameters are calculated, the backwards and forwards mach numbers of the detonation wave are obtained. The calculation method of thermal efficiency and entropy production with detonating combustion is deduced. At the different pressure ratios, the variety rule of thermal efficiency and entropy production are calculated. Finally, the detonation cycle is compared with Brayton cycle and Humphrey cycle, the results show that the detonation cycle is higher than the Brayton cycle and the Humphrey cycle in cycle thermal efficiency.