The thermal decomposition behaviors,including weight loss,heat flow and gaseous decomposition products of cashew nut shell liquid(CNSL) modified thermoplastic phenolic resin were investigated by TG-DSC-MS coupling techniques at different kinds of atmosphere.The kinetic parameters of CNSL modified thermoplastic phenolic resin were obtained from equation Coats-Redfern.The results showed that the atmosphere had an obvious effect on the pyrolysis of sample.Compared with that at N2 atmosphere,two major weight loss steps at air atmosphere existed,the total weight loss steps and temperature zones both also increased,and the thermal decomposition was more complete.At N2 atmosphere,the major weight loss zone showed endothermic in the DSC curves at different heating rates.At air atmosphere,the thermic response depended on the heating rates in the first major weight loss stage,but appearing exothermic in the second weight loss stage.The pyrolysis kinetics could be simplified as a model of a first-order reaction with four sections model at N2 atmosphere and another model of a first-order reaction with six sections at air atmosphere while α value varied from 0.10 to 0.90.In N2 atmosphere,the activation energies at different stages were 17，65，32,13 kJ?mol-1,respectively,and in air atmosphere,the activation energies at different stages were 72，23，14，12，19,57 kJ?mol-1,respectively.The signal intensity of ion current varied with temperature,and the atmosphere had an obvious effect on the gaseous decomposition products.In inert atmosphere(Ar),CNSL modified thermoplastic phenolic resin more easily cracked into aromatic hydrocarbons,e. g. benzene, toluene, dimethylbenzene, trimethylbenzene, ethyltoluene，ethylbenzene，phenol，methyl phenol，dimethylphenol，trimethylphenol, and alkanes，e.g.ethanol，methane，propane，butane，hexane，pentane.The aromatic hydrocarbons were the main gas products,which productions were up to a peak at 305-333 ℃and another peak at 408-460 ℃,respectively.In air atmosphere,the gaseous products were mainly H2O，CO2 and formic acid.Furthermore,the relative contents of H2O，CO2 and formic acid increased obviously.Only a few of aromatic hydrocarbons,eg.benzene and phenol were detected in the first major weight loss stage without any alkanes.