Currently, LBS (location-based service) is widely employed in many mobile devices, making the technology for processing moving object data underlying the road network to become a research hotspot in the community of spatio-temporal processing techniques. This paper intends to survey the previous work from three aspects including index structures, query approaches and privacy protection. First, the various index structures are classified into three groups:hierarchical, distributed and broadcast, and comparisons are made based on in-depth analysis. Second, the query approaches are divided into four categories by their purposes:single-object continuous query, multi-object parallel query, shortest path query and road-network keyword query. For each category, its basic strategies are introduced. In addition, methods on moving object privacy protection are also studied. The challenges on these technologies are projected in the end.