A method and device for monitoring paging signals are provided. A method of DRX cycle extension for a mobile terminal in an IDLE mode is provided. The method is used to extend the current DRX cycle. A longer paging cycle is designed by extending a UE-specific paging cycle or introducing a new coefficient in system information. A method for extending the SFN is proposed in the invention. A boundary and a serial number of the SFN in the longer wrap around are indicated by the SI. To avoid a situation in which the high paging load occurs in certain paging frames or subframes, the UE_ID is extended in the invention. The proposed mechanism can flexibly adjust the paging cycle and the SFN extension to meet the actual requirements. The long DRX cycle can save a lot of power consumption of the mobile terminals in the IDLE mode.