In wireless sensor network, a lot of sensory traffic with redundancy is produced due to massive node density and their diverse placement. This causes the decline of scarce network resources such as bandwidth and energy, thus decreasing the lifetime of sensor network. Recently, mobile agent is proposed as a solution to overcome these problems. Mobile agent accounts for performing data processing and making data aggregation decisions at nodes rather than bring data back to a central processor (sink). Using this approach, redundant sensory data will be eliminated. However, carrying a huge amount of aggregated data among source nodes, using mobile agent, requires immensely planned routing. This is to avoid hastily burning source nodes energy in interest region. Towards this end, we propose a novel approach to achieve optimal routing path for mobile agent. Our proposed approach has two folds. Firstly, Dijkstra's algorithm is used to generate a complete graph to connect all source nodes. Secondly, genetic algorithm is performed on a completed graph to generate best approximated route. To demonstrate the feasibility of our approach, formal analysis and experimental results are presented.