A method for power adjustment, comprising: receiving (101; 202), by a user equipment, UE, downlink control information that is sent by a base station and carries a transmit power control, TPC, command; determining (102; 203), by the UE, according to a power control command field in the TPC command and a first condition, a power control value corresponding to the power control command field; wherein the first condition is: information of a time when the UE receives the downlink control information; or information of a position of a physical downlink control channel, PDCCH, candidate; or information of a non-TPC command in the downlink control information; or a power control value preset in the UE; or indication information that is sent by the base station and used to indicate the power control value; and wherein when the first condition is the information of the position of the PDCCH candidate, the determining, by the UE, according to the first condition, the power control value corresponding to the power control command field, comprises: if the information of the position of the PDCCH candidate is L {( Y k + m')mod └ N CCE, k / L ┘}+ i, and the parameter m' is N, then determining, by the UE, that the power control value corresponding to the power control command field is 3dB; if the information of the position of the PDCCH candidate is L {( Y k + m')mod └ N CCE,k / L ┘}+ i, and the parameter m' is M, then determining, by the UE, that the power control value corresponding to the power control command field is -3dB; wherein N is an odd number, M is an even number; or, N is an even number, M is an odd number; wherein, N CCE,k is a number of control channel elements, CCEs, in a sub-frame whose reference number is K; i = 0,···, L -1, L is a number of CCEs contained in a PDCCH at a current aggregation level; m'=m + M -n CI, n CI is a carrier indicator, m= 0,···, M -1, Y k =( A · Y k -1)mod D, Y -1 = n RNTI ≠0, A = 39827, D = 65537; when n CI exists, the value of n CI is an arbitrary integer of 0 to 7; when n CI does not exist, m' = m; the radio network temporary identifier, RNTI, is an identification of the UE. receiving (101; 202), by a user equipment, UE, downlink control information that is sent by a base station and carries a transmit power control, TPC, command; determining (102; 203), by the UE, according to a power control command field in the TPC command and a first condition, a power control value corresponding to the power control command field; wherein the first condition is: information of a time when the UE receives the downlink control information; or information of a position of a physical downlink control channel, PDCCH, candidate; or information of a non-TPC command in the downlink control information; or a power control value preset in the UE; or indication information that is sent by the base station and used to indicate the power control value; and information of a time when the UE receives the downlink control information; or information of a position of a physical downlink control channel, PDCCH, candidate; or information of a non-TPC command in the downlink control information; or a power control value preset in the UE; or indication information that is sent by the base station and used to indicate the power control value; and wherein when the first condition is the information of the position of the PDCCH candidate, the determining, by the UE, according to the first condition, the power control value corresponding to the power control command field, comprises: if the information of the position of the PDCCH candidate is L {( Y k + m')mod └ N CCE, k / L ┘}+ i, and the parameter m' is N, then determining, by the UE, that the power control value corresponding to the power control command field is 3dB; if the information of the position of the PDCCH candidate is L {( Y k + m')mod └ N CCE,k / L ┘}+ i, and the parameter m' is M, then determining, by the UE, that the power control value corresponding to the power control command field is -3dB; if the information of the position of the PDCCH candidate is L {( Y k + m')mod └ N CCE, k / L ┘}+ i, and the parameter m' is N, then determining, by the UE, that the power control value corresponding to the power control command field is 3dB; if the information of the position of the PDCCH candidate is L {( Y k + m')mod └ N CCE,k / L ┘}+ i, and the parameter m' is M, then determining, by the UE, that the power control value corresponding to the power control command field is -3dB; wherein N is an odd number, M is an even number; or, N is an even number, M is an odd number; wherein, N CCE,k is a number of control channel elements, CCEs, in a sub-frame whose reference number is K; i = 0,···, L -1, L is a number of CCEs contained in a PDCCH at a current aggregation level; m'=m + M -n CI, n CI is a carrier indicator, m= 0,···, M -1, Y k =( A · Y k -1)mod D, Y -1 = n RNTI ≠0, A = 39827, D = 65537; when n CI exists, the value of n CI is an arbitrary integer of 0 to 7; when n CI does not exist, m' = m; the radio network temporary identifier, RNTI, is an identification of the UE.