This paper attempts to demonstrate the technology evolution in the field of smart grid. Technology evolution is presented through visualizing the timeline plot where each community is drawn as a function of their size, age, and time. To connect inter-year communities, the relatively weak communities are eliminated, and then the temporal relations among them are created in terms of the overlapped percentages from communities of previous year to those of the current year. Parts of relations with insignificant linkage strength are removed, leaving several community evolving trajectories for further analysis. The timeline plot clearly shows how communities of smart grid propagated and interrelated over time and could be used to explore the technological changes from the perspective of survival, birth, death, branching, or merging.