To identify whether hydroxylamine hydrochloride(HH) and N-methyl hydroxylamine hydrochloride(NMHH) are of autocatalysis characteristic, differential scanning calorimeter(DSC) and accelerating rate calorimeter(ARC) were used to test their thermal decomposition behaviors.Both dynamic and isothermal DSC results indicate an autocatalysis characteristic during their decompositions.And the heat of decomposition under 10 ℃·min^-1 were 2284.85 J·g^-1, 2188.41 J·g^-1 for HH and NMHH, respectively.ARC data show that the total decomposition time for HH and NMHH are both less than 30 min, and the maximum temperature rise rate are 193.4 ℃·min^-1, 218.9 ℃·min^-1, and the thermal decomposition very violent.Comparisons of ARC data of autocatalysis materials(HH, NMHH, trinitrotoluene(TNT) and so on) with that of non-autocatalysis materials(tert-butyl peroxy benzoate(TBPB), isooctyl nitrate(EHN) and di-tert-butyl peroxide(DTBP))show that the time difference from initial heat release to maximum temperature rise rate(t_0-max) for non-autocatalytic decomposition is much longer than that for autocatalytic decomposition, and the thermal inertia factor makes little influence on the law.So, the adiabatic test data t_0-max can be used to identify autocatalytic decomposition.