The effects of two nano burning rate catalysts (nano lead 2,4-dihydroxybenzoate and nano lead phthalate) on thermal decomposition of double-based propellants were studied using TG-DSC-IR simultaneous techniques and combined solid reaction cell in-situ and RSFT-IR. The characteristic values for TG-DTG and DSC of the condensed phase and the gas products were measured in real time. Results show that the nano lead salt catalysts change on the characteristic values of the thermal decomposition,and shorten the decomposition course and accelerate the exothermic rating. The split of O—NO₂ bond and framework in NC/NG component are facilitated. The relative quantities of CH₂O,CO and CO₂ (with negative forming heat ΔH^o_f) produced from the decomposition of NC/NG components increase. Compared with the blank control propellant,the exothermic rating of the propellants with n-β-Pb and n-PhtP increase from 29.5 J?g^-1?℃^-1 to 31.1 J?g^-1?℃^-1 and 31.4 J?g^-1?℃^-1 respectively; the ratios of CH₂O/NO₂ increase from 1.77 to 2.45 and 2.60 respectively; the ratios of CO/NO₂ increase from 0.071 to 0.079 and 0.090 respectively. The propellant with nano lead phthalate has the rapidest exothermic rating,and the largest relative quantity of CH₂O and CO,and the highest burning rate too.