Smart Grid is the trend of next generation electrical power system which makes the power grid intelligent and energy efficient. It requires high level of network reliability to support the two-way communication among electrical services, electrical units such as smart meters, and applications. The wireless mesh network infrastructure can provide redundant routes for the smart grid commu nication network to ensure the network availability. Also due to its high level of flexibility and scalability features that make it become a promising solution for smart grid. However, similar with many other distributed ad-hoc networks, trust is a critical issue for wireless mesh networks. In this paper, we proposed a novel trust-based geographical routing protocol, named as Dynamic Trust Electi ve Geo Routing (DTEGR), which allows peers in a smart grid system to adjust their interaction behaviours based on the trustworthiness of others. The simulation studies have confirmed that DTEGR can achieve better routing performance in different network scenarios, and also to achieve high level of reliable data transmission in smart grid communication networks.