Dynamic Route Guidance (DRG) system, which determines the traveling routes of vehicles, alleviates traffic problems in urban areas. On the other hand, ad-hoc network composed of vehicles, called VANET attracts attention from many researchers and VANET-based DRG systems are proposed. However, the existing DRG systems do not consider that degradation of communication performance causes degradation of application performance. Packet loss of traffic information hinders determining proper travelling routes. In this paper, we propose VANET-based DRG system with dynamic communication path selection by considering vehicle density, called DRG-DCPS. Each vehicle acquires traffic information by a request/response packet. Relay vehicles select crowded road segments as packet paths to improve communication performance. As a result, since each vehicle receives traffic information more correctly and can select appropriate travelling routes. To confirm effectiveness of DRG-DCPS, we implemented on a simulation environment integrating traffic simulator and network simulator.