A common view of modeling social worm propagation is topology construction for social networking layer and human behavior modeling for message checking activity. However, due to the existence of human mobility behavior, traditional analytical models have not been suitable for the propagation dynamics of social worms nowadays, which results in underestimating the scale of infected network and lacking a comprehensive and accurate abstraction for human behaviors. This letter proposes a novel model to understand the propagation dynamics of social worms in hierarchical networks based on the temporal characteristic of human mobility. We characterize the infection scale and the spread speed for social worms adopting discrete model and difference-equation method. Our simulations and analysis show our model to approximate the complicated propagation behaviors of social worms more accurately, and we give two quantitative conclusions on the range of final infection scale and the fastest spread speed. In addition, the results indicate the rationality and validity of our conclusions.