The invention provides a control information transmission method and device, and the method is used for a control information transmitting end and comprises the steps: enabling a first part of controlinformation to occupy a first time-frequency resource through a first physical layer channel, and transmitting the first part of control information to a control information receiving end; sending first indication information to the control information receiving end, wherein the first indication information being used for indicating the size of a second time-frequency resource, the second time-frequency resource being a time-frequency resource occupied by transmission of a second part of control information; and enabling the second part of control information to occupy the second time-frequency resource through a second physical layer channel and to be sent to the control information receiving end. Therefore, the control information receiving end can receive the second part of control information according to the indication of the control information transmitting end without blind detection, the blind detection complexity is reduced, and the communication quality of direct connectioncommunication is improved.