The invention discloses a calling method and a device of a network telephone, and the method is applied in a system comprising a voice server and a plurality of IP phones, and comprises the following steps: using the voice server to receive a user name request which is sent by the IP phone and carries a called telephone number, inquiring user name which corresponds to the called telephone number in the corresponding relationship between the stored telephone numbers and the user names, and sending the inquired user name to the IP phone; and using the voice server to receive a call request sentby the IP phone, and originating a call to the corresponding IP phone according to the called telephone number carried in the call request and the called user name. The method and the device can solve the problem of mutual calling and call forwarding among users in an Intranet, and be conductive to improving the user experience.