With more and more researches focused on food safety, time temperature indicators (TTIs) have been developed to monitor or indicate the shelf lives correspondingly. TTIs were classified into three types including physical, chemical and biological ones. Their working principles, characteristics, research and application progresses were reviewed. Meanwhile, three aspects of TTI were pointed out as the direction of further research, i.e., the condition-activated patterns, the matching between the rate of spoilage of food and TTI indication, and the development of new manufacturing methods such as applications in printing or coating.