A communications device and method for a carrier search are provided. The communication apparatus includes an RF signal processing device, a processor, and a memory device. The RF signal processing device receives a plurality of main system information and extra system information broadcasted by service networks. The processor is configured to check whether the extra system information corresponding to a second cell has been broadcasted by a detected network when a first center frequency of a first cell corresponding to a target radio access technology has been searched, and search a second center frequency of the second cell according to the extra system information corresponding to the second cell. All or a port of carriers are skipped according to the extra system information corresponding to the second cell. The memory device stores the main and extra system information received from detected service networks.