The work aims to research the chromogenic reaction kinetic law of 2,4-hexadiyn-1,6-bis(ethylurea) (KE) subject to solid state polymerization reaction, so as to provide guidance for its usage as the commercialized time temperature indicator. The chromogenic reaction kinetic law of 2,4-hexadiyn-1,6-bis(ethylurea) in the process of polymerization reaction was studied in the single factor method from such three aspects as concentration, time and temperature. The optical density was measured with spectroeye. Moreover, the order of reaction and reaction activation energy of polymerization reaction were obtained through calculation. The results demonstrated that the rate of KE polymerization increased as the concentration or temperature rose, and elevated initially then slightly decreased with heating time prolonged; during the above-mentioned conditions, the time temperature indicator’s color constantly became darker. The order of reaction and the activation energy calculated of polymerization reaction were respectively 0.31 and 37.09 kJ/mol. As a new type of time temperature indicator, the visual response signal of KE is easy to be identified; through color change of the indicator, the remaining shelf life of different products can be detected. According to its activation energy value, the range of the product’s activation energy to be indicated by the time temperature indicator is 12 to 61 kJ/mol.