The Taguchi method is a powerful approach in Design of experiments for quantifying multiple parameters. In ad-hoc network multi-constrained Quality of Service routing protocol designs, parameters such as the number of nodes, node mobility, transmission range, traffic load, end -to -end delay, and throughput will play a significant impact on the performance of routing protocol. To analyze the performance variation of routing protocols such as Dynamic Source Routing (DSR), Priority Aware – DSR (PA-DSR), and Adaptive Multi-constrained Quality of Service (AMQoS) in consideration of various parameters numerous experiments are designed by incorporating Taguchi method. The number of nodes and mobility speed are considered as a control factors and Signal to Noise Ratio (SNR), Transmission speed (Tx), Packet load are considered as a noise factors in the analysis of routing protocols. Total of 48 experiments were carried out in Network Simulator-2 as planned in orthogonal array of design of experiments. Finally ANOVA test is carried out to prove the performance variation of designed experiments with Taguchi method. The significance of AMQOS in comparison with the DSR and PA-DSR proved to be higher for more number of nodes and high mobility.