An information transmission method for enabling a base station to transmit first user control information of a first user on an Enhanced physical downlink control channel, the information transmission method comprises: an allocation step of, according to a search space allocation mode, performing a search space allocation in a target resource consisting of at least two resource subsets and allocating, for the first user, a first search space capable of transmitting the first user control information, the relationship between a number of subsets and a number of resources being determined on the basis of dynamic information; and a first transmission step of transmitting the first user control information via the first search space so that the first user can acquire the first user control information from the first search space according to the search space allocation mode; wherein the allocation step comprises: a pre-allocation step of, according to the search space allocation mode, performing the search space allocation in a current target resource consisting of at least two resource subsets, to obtain an allocation result; a judgment step of, according to the allocation result, judge whether or not the first search space currently allocated for the first user is a search space where no collision occurs, to obtain a judgment result; and an execution step of, when the judgment result is yes, proceeding to the first transmission step, and otherwise extending the target resource, and then performing the search space allocation again, wherein a correspondence between the resource subset and a size of the user control information is recorded in the search space allocation mode, and the pre-allocation step comprises: according to the correspondence between the resource subset and the size of the user control information, determining a first resource subset corresponding to a size of the first user control information from the at least two resource subsets; and performing the search space allocation in the first resource subset, to obtain the allocation result. an allocation step of, according to a search space allocation mode, performing a search space allocation in a target resource consisting of at least two resource subsets and allocating, for the first user, a first search space capable of transmitting the first user control information, the relationship between a number of subsets and a number of resources being determined on the basis of dynamic information; and a first transmission step of transmitting the first user control information via the first search space so that the first user can acquire the first user control information from the first search space according to the search space allocation mode; wherein the allocation step comprises: a pre-allocation step of, according to the search space allocation mode, performing the search space allocation in a current target resource consisting of at least two resource subsets, to obtain an allocation result; a judgment step of, according to the allocation result, judge whether or not the first search space currently allocated for the first user is a search space where no collision occurs, to obtain a judgment result; and an execution step of, when the judgment result is yes, proceeding to the first transmission step, and otherwise extending the target resource, and then performing the search space allocation again, wherein a correspondence between the resource subset and a size of the user control information is recorded in the search space allocation mode, and the pre-allocation step comprises: according to the correspondence between the resource subset and the size of the user control information, determining a first resource subset corresponding to a size of the first user control information from the at least two resource subsets; and performing the search space allocation in the first resource subset, to obtain the allocation result. a pre-allocation step of, according to the search space allocation mode, performing the search space allocation in a current target resource consisting of at least two resource subsets, to obtain an allocation result; a judgment step of, according to the allocation result, judge whether or not the first search space currently allocated for the first user is a search space where no collision occurs, to obtain a judgment result; and an execution step of, when the judgment result is yes, proceeding to the first transmission step, and otherwise extending the target resource, and then performing the search space allocation again, wherein a correspondence between the resource subset and a size of the user control information is recorded in the search space allocation mode, and the pre-allocation step comprises: according to the correspondence between the resource subset and the size of the user control information, determining a first resource subset corresponding to a size of the first user control information from the at least two resource subsets; and performing the search space allocation in the first resource subset, to obtain the allocation result. according to the correspondence between the resource subset and the size of the user control information, determining a first resource subset corresponding to a size of the first user control information from the at least two resource subsets; and performing the search space allocation in the first resource subset, to obtain the allocation result.