The "big data" era is characterized by an explosion of information in the form of digital data collections, ranging from scientific knowledge, to social media, news, and everyone's daily life. Valuable knowledge about multi-typed entities is often hidden in the unstructured or loosely structured but interconnected data. Mining latent structured information around entities uncovers semantic structures from massive unstructured data and hence enables many high-impact applications, including taxonomy or knowledge base construction, multi-dimensional data analysis and information or social network analysis.A mining framework is proposed, to solve and integrate a chain of tasks: hierarchical topic discovery, topical phrase mining, entity role analysis and entity relation mining. It reveals two main forms of structures: topical and relational structures. The topical structure summarizes the topics associated with entities with various granularity, such as the research areas in computer science. The framework enables recursive construction of phrase-represented and entity-enriched topic hierarchy from text-attached information networks. It makes breakthrough in terms of quality and computational efficiency. The relational structure recovers the hidden relationship among entities, such as advisor-advisee. A probabilistic graphical modeling approach is proposed. The method can utilize heterogeneous attributes and links to capture all kinds of semantic signals, including constraints and dependencies, to recover the hierarchical relationship with the best known accuracy.ii