The work aims to prepare a microbial time-temperature indicator, in order to characterize the freshness of fresh milk accurately. Microbial microcapsules were prepared by SPG membrane emulsification technology on the basis of Lactobacillus helveticus strains. Three kinds of solid microbial time-temperature indicators were made according to different proportions of microbial capsules and solid substrates. Their dynamic characteristics were studied by their color difference values. The test matching the applied fresh milk was carried out under the conditions of constant and variable temperatures. The difference of activation energy between three TTIs at different proportions and fresh milk was within 25 kJ/mol. When the ratio (g/mL) of microcapsule in mass to volume of solid matrix was 1∶2, the difference of equivalent temperature between the two indicators was 2.1 ℃ under variable temperature, and the error of TTI in predicting the end point of food shelf life was 3%. The microbial TTI prepared can accurately visualize the shelf life of fresh milk under constant and variable temperatures.