A method for transmitting a control channel, wherein the method is performed by a base station and the method comprises: determining m resource units used for transmitting a control channel to be transmitted, wherein an i th resource unit comprises n i first physical resource elements and k i second physical resource elements, and the second physical resource elements form multiple second physical resource element groups, wherein the first physical resource elements are used for transmitting the control channel to be transmitted in a localized transmission mode, the second physical resource elements are used for transmitting the control channel to be transmitted in a distributed transmission mode, and one of the n i first physical resource elements comprises at least two second physical resource elements, wherein m ≥ 1, n i ≥ 1, k i ≥ 1, 0 ≤ i ≤ m-1, and m, i, n i, and k i are all integers; when the control channel to be transmitted is transmitted in the distributed transmission mode, determining an aggregation level L of the control channel to be transmitted, wherein L ≥ 1, and L is an integer; determining, according to the aggregation level L, a number G L of second physical resource elements comprised in each of the second physical resource element groups, wherein the G L second physical resource elements comprised in each of the second physical resource element groups are located in ⌈ G L / q ⌉ first physical resource elements in the m resource units, wherein q indicates a number of second physical resource elements comprised in one of the n i first physical resource elements, ⌈ G L / q ⌉ indicates roundup of G L / q, G L ≥ 1, and G L is an integer; determining, according to the aggregation level L, a first control channel candidate at the aggregation level L, wherein the first control channel candidate corresponds to N L second physical resource element groups, wherein N L ≥ 1, and N L is an integer; and placing control information of the control channel to be transmitted, on physical resources to which the first control channel candidate is mapped, and transmitting the control information; wherein determining, according to the aggregation level L, a first control channel candidate at the aggregation level L comprises: determining, according to the aggregation level L, the number M of control channel candidates at the aggregation level L, wherein M is an integer, and M ≥ 1; mapping the M control channel candidates to physical resources in the m resource units; and selecting one first control channel candidate from the M control channel candidates. determining m resource units used for transmitting a control channel to be transmitted, wherein an i th resource unit comprises n i first physical resource elements and k i second physical resource elements, and the second physical resource elements form multiple second physical resource element groups, wherein the first physical resource elements are used for transmitting the control channel to be transmitted in a localized transmission mode, the second physical resource elements are used for transmitting the control channel to be transmitted in a distributed transmission mode, and one of the n i first physical resource elements comprises at least two second physical resource elements, wherein m ≥ 1, n i ≥ 1, k i ≥ 1, 0 ≤ i ≤ m-1, and m, i, n i, and k i are all integers; when the control channel to be transmitted is transmitted in the distributed transmission mode, determining an aggregation level L of the control channel to be transmitted, wherein L ≥ 1, and L is an integer; determining, according to the aggregation level L, a number G L of second physical resource elements comprised in each of the second physical resource element groups, wherein the G L second physical resource elements comprised in each of the second physical resource element groups are located in ⌈ G L / q ⌉ first physical resource elements in the m resource units, wherein q indicates a number of second physical resource elements comprised in one of the n i first physical resource elements, ⌈ G L / q ⌉ indicates roundup of G L / q, G L ≥ 1, and G L is an integer; determining, according to the aggregation level L, a first control channel candidate at the aggregation level L, wherein the first control channel candidate corresponds to N L second physical resource element groups, wherein N L ≥ 1, and N L is an integer; and placing control information of the control channel to be transmitted, on physical resources to which the first control channel candidate is mapped, and transmitting the control information; wherein determining, according to the aggregation level L, a first control channel candidate at the aggregation level L comprises: determining, according to the aggregation level L, the number M of control channel candidates at the aggregation level L, wherein M is an integer, and M ≥ 1; mapping the M control channel candidates to physical resources in the m resource units; and selecting one first control channel candidate from the M control channel candidates. determining, according to the aggregation level L, the number M of control channel candidates at the aggregation level L, wherein M is an integer, and M ≥ 1; mapping the M control channel candidates to physical resources in the m resource units; and selecting one first control channel candidate from the M control channel candidates.