The invention discloses a resource reservation method and system. According to the resource reservation method, after a called terminal receives an inquiring request message sent by a calling terminal, an inquiring request response is sent to the calling terminal, wherein the inquiring request response comprises an indication message that whether the called terminal supports repeated consultations or not, and at least one resource parameter capable of being provided; when the calling terminal judges that the called terminal supports the repeated consultations according to the indication message, a resource parameter supported by the calling resource is selected from the resource parameters so as to generate a resource reservation message and carry out resource allocation according to the resource reservation message; the calling terminal sends the resource reservation message to the called terminal, and the called terminal carries out the resource allocation according to the resource reservation message. Whether both terminals participating in a call support the repeated consultations is consulted in advance, various resources needed when the both terminals carry out the repeated consultations can be reserved, and therefore repeated consultations in follow-up calls can be carried out normally.