The work aims to explore the color-changing mechanism of time-temperature indicator (TTI) based on gold nanoparticles and the influence of different preparation parameters on its kinetic parameters to provide basis for its practical application in food. Colloidal TTI was prepared based on the reduction reaction of gelatin and chloroauric acid. The absorbance of TTI was measured by a UV-visible spectrophotometer, and nonlinearly fitted to time. The effects of prepa-ration parameters on the reaction rate, color lifetime and activation energy were investigated with single-factor experiments. The gold nanoparticles produced in the TTI system made the TTI appear purple, and the increase in the number of gold nanoparticles caused the color of the TTI to become darker. When the dosage of gelatin was reduced and the mass ratio of gelatin-chloroauric acid was unchanged, or when the dosage of gelatin was unchanged and the mass ratio of gela-tin-chloroauric acid was increased, the reaction rate of the TTI system slowed and the color change life prolonged. The gelatin-chloroauric acid mass ratio determined the activation energy of the TTI system. The activation energy of TTI was concentrated, ranging from 77.89 to 84.58 kJ/mol. TTI has the potential to monitor the food that are spoiled due to fat oxidation. By adjusting the preparation parameters of TTI, its color lifetime can be changed to match food with different shelf life.