Abstract: TDI in the air workshop has been analyzed with the Tenax/Adsorption Concentration/Thermal Desorption/Gas Chromatography.The suitable adsorption flow of tenax is 0.5L/min and the appropriate thermal desorption temperature is 280℃。The minimum adsorption capacity of tenax is 0.41mg TDI/g tenax and the maximum is 474g TDI/g tenax.The relative standard deriation of the method is 0.38%;The coefficient of variation is 3.0% and the recovery rate is 98.2%.