A method for managing a modulation and coding scheme, MCS, comprising: a base station obtaining a downlink channel quality indicator, CQI, and MCS when a block error ratio of a trunking terminal reaches a pre-stored block error ratio threshold; the base station comparing a current CQI of a group with a locally stored CQI reported by the group, wherein the CQI reported by the group is a minimum in received CQIs reported by trunking terminals in the group respectively; and if a comparison result is that the CQI reported by the group is smaller than the current CQI of the group, the base station initiating an operation of updating an MCS value; wherein, the base station initiating an operation of updating the MCS comprises: if an MCS reported by the group is smaller than or equal to the group MCS, decreasing a group MCS outer loop value of the base station by one order, wherein the MCS reported by the group is a minimum of the MCSs corresponding to the CQIs reported when the block error ratio of the trunking terminal reaches the pre-stored block error ratio threshold, the group MCS is an MCS determined during a previous scheduling; if a counter for group outer loop scheduling reaches a preset threshold of a counter for MCS outer loop scheduling, the base station increasing the group MCS outer loop value by one order, and clearing the counter for group outer loop scheduling; wherein, when the MCS corresponding to the CQI reported by the group in a pre-stored group CQI and MCS mapping table is smaller than the group MCS, or, when the MCS reported by the group is smaller than or equal to the group MCS, the counter for group outer loop scheduling is cleared; every time the base station periodically schedules the MCS value, the counter for group outer loop scheduling is increased by one; and according to an adjusted MCS outer loop value, the base station determining the MCS value of the scheduling of this time. a base station obtaining a downlink channel quality indicator, CQI, and MCS when a block error ratio of a trunking terminal reaches a pre-stored block error ratio threshold; the base station comparing a current CQI of a group with a locally stored CQI reported by the group, wherein the CQI reported by the group is a minimum in received CQIs reported by trunking terminals in the group respectively; and if a comparison result is that the CQI reported by the group is smaller than the current CQI of the group, the base station initiating an operation of updating an MCS value; wherein, the base station initiating an operation of updating the MCS comprises: if an MCS reported by the group is smaller than or equal to the group MCS, decreasing a group MCS outer loop value of the base station by one order, wherein the MCS reported by the group is a minimum of the MCSs corresponding to the CQIs reported when the block error ratio of the trunking terminal reaches the pre-stored block error ratio threshold, the group MCS is an MCS determined during a previous scheduling; if a counter for group outer loop scheduling reaches a preset threshold of a counter for MCS outer loop scheduling, the base station increasing the group MCS outer loop value by one order, and clearing the counter for group outer loop scheduling; wherein, when the MCS corresponding to the CQI reported by the group in a pre-stored group CQI and MCS mapping table is smaller than the group MCS, or, when the MCS reported by the group is smaller than or equal to the group MCS, the counter for group outer loop scheduling is cleared; every time the base station periodically schedules the MCS value, the counter for group outer loop scheduling is increased by one; and according to an adjusted MCS outer loop value, the base station determining the MCS value of the scheduling of this time. if an MCS reported by the group is smaller than or equal to the group MCS, decreasing a group MCS outer loop value of the base station by one order, wherein the MCS reported by the group is a minimum of the MCSs corresponding to the CQIs reported when the block error ratio of the trunking terminal reaches the pre-stored block error ratio threshold, the group MCS is an MCS determined during a previous scheduling; if a counter for group outer loop scheduling reaches a preset threshold of a counter for MCS outer loop scheduling, the base station increasing the group MCS outer loop value by one order, and clearing the counter for group outer loop scheduling; wherein, when the MCS corresponding to the CQI reported by the group in a pre-stored group CQI and MCS mapping table is smaller than the group MCS, or, when the MCS reported by the group is smaller than or equal to the group MCS, the counter for group outer loop scheduling is cleared; every time the base station periodically schedules the MCS value, the counter for group outer loop scheduling is increased by one; and according to an adjusted MCS outer loop value, the base station determining the MCS value of the scheduling of this time.