A method for selecting a transport format in an uplink multiple-input multiple-output system, characterized by comprising: receiving, by a user equipment UE, a reference E-TFC set and a primary-stream channel quality difference in a dual-stream transmission mode that are sent by a base station; acquiring, by the user equipment according to a primary-stream serving grant SG allocated by the base station to the user equipment within a transmission time interval TTI, a first transmit power offset A ed 2 of a primary stream granted by the base station; when transmit power of the primary stream is obtained according to primary-stream transmit power granted by the base station, acquiring, by the user equipment, when inter-stream interference is considered and a transmit power offset of the primary stream is A ed 2, a first transport format combination indicator E-TFCI 1 of the primary stream according to the primary-stream channel quality difference and the A ed 2; when the transmit power of the primary stream is obtained according to remaining transmit power, which is calculated according to a limit value of maximum transmit power of the user equipment, calculating, by the user equipment, a second transmit power offset A ed ′ 2 of the primary stream according to the remaining transmit power, and calculating, when inter-stream interference is considered and the transmit power offset of the primary stream is A ed ′ 2, an equivalent transmit power offset A edm 1 ′ 2 of the primary stream according to the primary-stream channel quality difference, the A ed 2, and the A ed ′ 2; and calculating, by the user equipment, when inter-stream interference is considered and the transmit power offset of the primary stream is A ed ′ 2, a second transport format combination indicator E − TFCI 1 ′ of the primary stream according to the reference E-TFC set and the A edm 1 ′ 2; and selecting, by the user equipment from the E-TFCI 1 and the E − TFCI 1 ′, an indicator, which has a smaller value, as a third transport format combination indicator E − TFCI 1 " of the primary stream corresponding to a transport format used by the user equipment to send uplink data. receiving, by a user equipment UE, a reference E-TFC set and a primary-stream channel quality difference in a dual-stream transmission mode that are sent by a base station; acquiring, by the user equipment according to a primary-stream serving grant SG allocated by the base station to the user equipment within a transmission time interval TTI, a first transmit power offset A ed 2 of a primary stream granted by the base station; when transmit power of the primary stream is obtained according to primary-stream transmit power granted by the base station, acquiring, by the user equipment, when inter-stream interference is considered and a transmit power offset of the primary stream is A ed 2, a first transport format combination indicator E-TFCI 1 of the primary stream according to the primary-stream channel quality difference and the A ed 2; when the transmit power of the primary stream is obtained according to remaining transmit power, which is calculated according to a limit value of maximum transmit power of the user equipment, calculating, by the user equipment, a second transmit power offset A ed ′ 2 of the primary stream according to the remaining transmit power, and calculating, when inter-stream interference is considered and the transmit power offset of the primary stream is A ed ′ 2, an equivalent transmit power offset A edm 1 ′ 2 of the primary stream according to the primary-stream channel quality difference, the A ed 2, and the A ed ′ 2; and calculating, by the user equipment, when inter-stream interference is considered and the transmit power offset of the primary stream is A ed ′ 2, a second transport format combination indicator E − TFCI 1 ′ of the primary stream according to the reference E-TFC set and the A edm 1 ′ 2; and selecting, by the user equipment from the E-TFCI 1 and the E − TFCI 1 ′, an indicator, which has a smaller value, as a third transport format combination indicator E − TFCI 1 " of the primary stream corresponding to a transport format used by the user equipment to send uplink data.