Abstract: Routing in mobile ad-hoc network (MANET) is a challenging task. Thus, the purpose of this paper is to study the multiple performance of metrics optimisation of the routing process in MANET. The Taguchi method, combined with the grey relational analysis have been employed to determine the optimal factor combinations, as well as their significance. Using L8 orthogonal array design, network scenarios are simulated with network simulator 2. The effects of terrain, number of nodes, number of sources, number of packets transmitted, speed and pause time are optimised for maximum throughput and minimum routing overhead and packet drops. Five confirmatory tests are conducted, and the results indicate that the average values of the Relational Grade (GRG) fall within the 95% confidence interval, hence the experiment is proven to be reliable and repeatable. According to the analysis of variance of the GRG, the number of sources is the most significant factor that affects the multiple performance metrics.