A hyper system frame number determining method, comprising: agreeing by an access network device with a core network device on a preconfigured time being a time at which a hyper system frame number, HSFN, counts from 0; determining, by the access network device, a first HSFN, and a first system frame number, SFN, wherein the first HSFN is calculated by dividing the time difference between the preconfigured time and the time when eDRX is activated by the duration of a hyper frame, and the first SFN is computed to be 0 at the time at which eDRX is enabled; determining, by the access network device, an HSFN adjustment value based on the first SFN and a second SFN, wherein the second SFN is an SFN used at the time at which the access network device enables the eDRX; wherein the HSFN adjustment value is determined to be 0 if an absolute value of a difference between the first SFN and the second SFN is less than or equal to a preset threshold; the HSFN adjustment value is determined to be m if the difference between the first SFN and the second SFN is greater than the preset threshold, wherein m is an integer greater than 0; or the HSFN adjustment value is determined to be n if the difference between the second SFN and the first SFN is greater than the preset threshold, wherein n is an integer less than 0; and wherein the preset threshold is a positive integer greater than or equal to 0, and less than 1024; determining, by the access network device, a sum of the HSFN adjustment value and the first HSFN as the second HSFN; and sending, by the access network device to the core network device, the second HSFN and a time at which the second HSFN is enabled. agreeing by an access network device with a core network device on a preconfigured time being a time at which a hyper system frame number, HSFN, counts from 0; determining, by the access network device, a first HSFN, and a first system frame number, SFN, wherein the first HSFN is calculated by dividing the time difference between the preconfigured time and the time when eDRX is activated by the duration of a hyper frame, and the first SFN is computed to be 0 at the time at which eDRX is enabled; determining, by the access network device, an HSFN adjustment value based on the first SFN and a second SFN, wherein the second SFN is an SFN used at the time at which the access network device enables the eDRX; wherein the HSFN adjustment value is determined to be 0 if an absolute value of a difference between the first SFN and the second SFN is less than or equal to a preset threshold; the HSFN adjustment value is determined to be m if the difference between the first SFN and the second SFN is greater than the preset threshold, wherein m is an integer greater than 0; or the HSFN adjustment value is determined to be n if the difference between the second SFN and the first SFN is greater than the preset threshold, wherein n is an integer less than 0; and wherein the preset threshold is a positive integer greater than or equal to 0, and less than 1024; determining, by the access network device, a sum of the HSFN adjustment value and the first HSFN as the second HSFN; and sending, by the access network device to the core network device, the second HSFN and a time at which the second HSFN is enabled.