Medium access control (MAC) and routing protocols play a vital role in mobile ad hoc networks (MANET) performance. This paper applies Kriging to predict the relationship between the perceived quality of service (QoS) of Voip services and the protocols of MANET such as IEEE 802.11 MAC protocol and ad hoc on-demand distance vector (AODV) routing protocol. First of all, we present a concept of MANET and the E-Model for calculating the mean opinion score (MOS) representing perceived QoS of VoIP. We select each operation parameter of IEEE 802.11 and AODV, respectively, as two design variables and MOS as a response variable. We predict a response model of the perceived QoS of VoIP application using Kriging. Finally, cross-validation (Q-1 and Q-2) statistics and double-kring are used to check the validity of the model predicted by the Kriging.