A method for indicating a transmission time interval, comprising: receiving an access preamble from a user equipment, UE, wherein the access preamble carries a signature; and determining whether a cell where the UE is located is configured with an extended acquisition indicator, EAI, and sending, on an acquisition indicator channel, AICH, of an access timeslot corresponding to an access timeslot where the access preamble is received, an acquisition indicator, AI, corresponding to the signature of the access preamble; wherein if a value of the AI is a first value, default resources associated with the signature of the access preamble which are used by the UE and a transmission time interval, TTI, type requested by the UE are allocated and indicated, or default resources associated with the AI corresponding to the signature of the access preamble which are used by the UE and a TTI type requested by the UE are allocated and indicated, wherein the method further comprises: if the cell where the UE is located is configured with an EAI and the value of the AI is a second value being different from the first value, sending an EAI to the UE to indicate rejection of the access request of the UE, or allocate and indicate a resource index used by the UE and a TTI type, or indicate the UE to execute a fallback operation, characterized in: that the sending an EAI to the UE to indicate rejection of the access request of the UE, or allocate and indicate a resource index used by the UE and a TTI type, or indicate the UE to execute a fallback operation comprises: sending two EAIs to the UE, wherein if the two EAIs comprises a NACK EAI and a non-NACK EAI, the non-NACK EAI is used to indicate the resource index used by the UE, and another TTI type different from the TTI type requested by the UE, or a preset TTI type, if the two EAIs do not comprise a NACK EAI, the two EAIs are used to instruct the UE to execute a fallback operation. receiving an access preamble from a user equipment, UE, wherein the access preamble carries a signature; and determining whether a cell where the UE is located is configured with an extended acquisition indicator, EAI, and sending, on an acquisition indicator channel, AICH, of an access timeslot corresponding to an access timeslot where the access preamble is received, an acquisition indicator, AI, corresponding to the signature of the access preamble; wherein if a value of the AI is a first value, default resources associated with the signature of the access preamble which are used by the UE and a transmission time interval, TTI, type requested by the UE are allocated and indicated, or default resources associated with the AI corresponding to the signature of the access preamble which are used by the UE and a TTI type requested by the UE are allocated and indicated, wherein the method further comprises: if the cell where the UE is located is configured with an EAI and the value of the AI is a second value being different from the first value, sending an EAI to the UE to indicate rejection of the access request of the UE, or allocate and indicate a resource index used by the UE and a TTI type, or indicate the UE to execute a fallback operation, characterized in: that the sending an EAI to the UE to indicate rejection of the access request of the UE, or allocate and indicate a resource index used by the UE and a TTI type, or indicate the UE to execute a fallback operation comprises: sending two EAIs to the UE, wherein if the two EAIs comprises a NACK EAI and a non-NACK EAI, the non-NACK EAI is used to indicate the resource index used by the UE, and another TTI type different from the TTI type requested by the UE, or a preset TTI type, if the two EAIs do not comprise a NACK EAI, the two EAIs are used to instruct the UE to execute a fallback operation. that the sending an EAI to the UE to indicate rejection of the access request of the UE, or allocate and indicate a resource index used by the UE and a TTI type, or indicate the UE to execute a fallback operation comprises: sending two EAIs to the UE, wherein if the two EAIs comprises a NACK EAI and a non-NACK EAI, the non-NACK EAI is used to indicate the resource index used by the UE, and another TTI type different from the TTI type requested by the UE, or a preset TTI type, if the two EAIs do not comprise a NACK EAI, the two EAIs are used to instruct the UE to execute a fallback operation. sending two EAIs to the UE, wherein if the two EAIs comprises a NACK EAI and a non-NACK EAI, the non-NACK EAI is used to indicate the resource index used by the UE, and another TTI type different from the TTI type requested by the UE, or a preset TTI type, if the two EAIs do not comprise a NACK EAI, the two EAIs are used to instruct the UE to execute a fallback operation.