Abstract: In order to use the microcapsules containing Lactobacillusacidophilus widely and provide theoretical basis for analyzing the shelf lifeof products, the thermal stability and thermodynamics of the microcapsules werestudied according to the number of survival bacteria. Results show that the deactivation constant of microcapsules rise gradually with the increase of temperature from 45℃ to 60℃, and the time periods of deactivation(D) are 140.85 h, 64.52 h, 31.06 h and 14.40 h, respectively when 90% bacteria in microcapsuleare dead; within this temperature range, the change value of temperature(Z) is15.20℃ when the change amount of D is 90%. The apparent active energy(E) is 124.43 kJ/mol calculated by Arrhenius equation.