Abstract: In order to understand the detonation characteristic of propane,a series of single detonation experiments was conducted with air,oxygen and air/oxygen as oxidizer in square detonation tube.Firstly the detonation performance of propane was studied.Secondly the characteristic of deflagration to detonation transition(DDT),spread rule of wave and flame were achieved under the condition of different equivalence ratio and degrees of nitrogen dilution.The ion-probes and pressure transducers were utilized to get the velocity and pressure in the tube,respectively.The results indicate:(1)C₃H₈/air mixtures could not form detonation wave,and that the DDT distance of C₃H₈/O₂ mixtures was very short,(2)the run-up distance was minimum for stoichiometric mixture,increasing as the nitrogen dilution became richer,and(3)shock and flame have similar change trend in DDT.