An embodiment of the present invention relates to the technical field of wireless communication. Disclosed are a transmit power control and power control method, system and device for solving the problem of user equipment unable to control the power of a PDCCH when reusing a TPC command, thus decreasing the PDCCH power accuracy. The method in the embodiment of the present invention comprises: determining whether the TPC domain in a first DCI format information is a non-TPC command after a user equipment receiving the first DCI format information; when the TCP domain of the first DCI format information received by the user equipment is a non-TPC command, and after receiving a second DCI format information in the downlink sub-frame receiving the first DCI format information, using the TPC command in the second DCI format information to control the PUCCH power. Employing the method of the present invention can improve the PUCCH power accuracy and the performance of the user equipment.