A method for a random access in a relay system, comprising steps of: determining, by a relay node RN, whether a random access is triggered; and if the random access is triggered, performing, by the RN, the random access by using a non-backhaul link subframe, wherein the method is characterized in that, for a contention-based random access, if Msg1 is limited to use uplink UL backhaul link BH subframes, the step of performing, by the RN, the random access by using a non-backhaul link subframe, comprises: selecting, by the RN, a preamble and a UL BH subframe, and sending the preamble to a network side by using random access channel RACH resources of the UL BH subframe; after detecting the preamble by the network side, sending, by the network side a random access response RAR message to the RN, and monitoring, by the RN, all downlink DL subframes with physical downlink control channels PDCCHs in an RAR window to receive the RAR message, and sending UL data to the network side by using uplink resources allocated through the RAR message; when the network side sends a contention resolution message according to the UL data, receiving, by the RN, the contention resolution message in the DL subframes with PDCCHs during a PDCCH if a mac contention resolution mac-ContentionResolution timer is running. determining, by a relay node RN, whether a random access is triggered; and if the random access is triggered, performing, by the RN, the random access by using a non-backhaul link subframe, wherein the method is characterized in that, for a contention-based random access, if Msg1 is limited to use uplink UL backhaul link BH subframes, the step of performing, by the RN, the random access by using a non-backhaul link subframe, comprises: selecting, by the RN, a preamble and a UL BH subframe, and sending the preamble to a network side by using random access channel RACH resources of the UL BH subframe; after detecting the preamble by the network side, sending, by the network side a random access response RAR message to the RN, and monitoring, by the RN, all downlink DL subframes with physical downlink control channels PDCCHs in an RAR window to receive the RAR message, and sending UL data to the network side by using uplink resources allocated through the RAR message; when the network side sends a contention resolution message according to the UL data, receiving, by the RN, the contention resolution message in the DL subframes with PDCCHs during a PDCCH if a mac contention resolution mac-ContentionResolution timer is running. selecting, by the RN, a preamble and a UL BH subframe, and sending the preamble to a network side by using random access channel RACH resources of the UL BH subframe; after detecting the preamble by the network side, sending, by the network side a random access response RAR message to the RN, and monitoring, by the RN, all downlink DL subframes with physical downlink control channels PDCCHs in an RAR window to receive the RAR message, and sending UL data to the network side by using uplink resources allocated through the RAR message; when the network side sends a contention resolution message according to the UL data, receiving, by the RN, the contention resolution message in the DL subframes with PDCCHs during a PDCCH if a mac contention resolution mac-ContentionResolution timer is running.