A network selection method automatically selects a communication network for a multi-mode mobile communication device, which has operability in two or more communication networks. Plural of digit map strings and a network priority setting are provided and stored in the mobile communication device. An input phone number is compared with all the digit map strings to obtain a match result. A communication network is selected by the mobile communication device among two or more communication networks based on a current network status, the match result, and the network priority setting.