The present invention is Voice over Internet Protocol: related to a call routing method in (VoIP Voice over Internet Protocol), in particular by using the network parameters that affect the sound quality (Voice Quality) on the IP (Internet Protocol) network, the speech quality the call routing method in VoIP with voice quality, the predictive value by performing a call routing to the gateway having the best voice quality predictive value at the gateway group grouping after forecasting to deliver the best voice service guarantee voice quality under limited circumstances It relates. Further, according to the present invention, the audio quality by using a measurement system to obtain speech quality prediction equation by regression analysis, packet delay for each destination gateway, the gateway using the Ping (Ping) technique in the VoIP network, packet loss, the packet length, to obtain a jitter sound quality by using a prediction equation seek predicted speech quality value for said each destination gateway, the prediction and the gateway is obtained from the plurality of destination gateway, the predicted transmit receive their voice quality value speech quality value and using a transmission received predicted speech quality value from said plurality of destination gateways to obtain a final predicted speech quality values, and wherein the gateway is configured as a gateway routing table in the gateway group table number of the access code is assigned, each gateway groups IP gateway by air Configure-less field and predict prediction MOS value of the field is the gateway group table comprising specifying the MOS value, and the gateway of the gateway comprises a gateway group obtained by the access code to the call routed to a gateway group for an access code, the call routing method is provided for performing the VoIP call routing to the gateway having the maximum prediction MOS value.