Interspecific trait variation has long been considered as a conceptual foundation for our understanding of species interactions and community structure. In particular, ecologists realize the important role that animal behavior plays in shaping ecological processes. Although most studies commonly supposed that the functional diversity occurs at the level of the species and ignored individual variation. Recently, an emerging field of interest in animal behavior, the studies of animal personalities focus on how individual differences in behavior, as well as behavioral correlations affect the fitness of individuals in various ecological contexts. "Animal personality" describes the common phenomenon that individual behavioral differences are consistent over time and across situations, which covers numerous traits, such as willingness to take risks, the reaction of an animal to novel environment, activity, aggressiveness, and sociality. The majority of theoretical and empirical studies suggest that personality differences are a widespread phenomenon throughout the animal kingdom, and it limits behavioral plasticity and explains non-optimal behavior, which has far-reaching implications for understanding the mechanism of species interactions and coexistence. In this article, we review the concepts, trait categories, and measurement methods of animal personality. We then aim to provide a comprehensive inventory of the potential consequences of personality differences for ecological and evolutionary patterns and processes, we discuss the ecological implications of personality, including life-history strategies, population distribution and abundance, species interactions, community structure and dynamics, ecosystem processes and disease and information transmission. In addition, a critical ecological and evolutionary issue is the need to better understand individual responses to human-induced rapid environmental change that often puts organisms in evolutionarily novel conditions. Behavior is predicted to be a major factor driving responses of individuals to global change because it largely determines how animals interact with the environment. This intraspecific trait variation differs strikingly in their ability to cope with responses to human activity and urbanization induced rapidly environmental change. Thus, incorporating animal personalities can provide great insight into our understanding of the ecological and evolutionary consequences of global change and help either aid declining species or better manage invasive or pest species. Moreover, we discuss the proximate and ultimate mechanisms underlying individual variation in personality traits, including the effects of ecological, genetic, physiological, and neuroendocrine factors on the maintenance of variation in personality traits in natural animal populations. The animal personality can form a key bridge in an interdisciplinary approach that integrates proximate mechanisms (genetics, development, and neuroendocrine bases) with ecology and evolution. Finally, the future research direction is prospected.