Disclosed is a weight factor matrix determining method for beamforming in a base station in order for inter-cell interference to be removed. The weight factor matrix determining method for beamforming which includes: determining a first transmission power for a first terminal being a target terminal and a second transmission power for a plurality of second terminals other than the target terminal; calculating an Eigen vector with an Eigen value for a ratio of the first and second transmission powers; and determining a weight factor matrix in a serving base station, with the calculated Eigen vector.