Embodiments of the present invention provide a communication method, a base station, and a terminal device. The method includes: transmitting, by a base station, signals to a terminal device by using n port groups, where each of the n port groups includes at least two ports; and receiving, by the base station, s first linear combination coefficient groups transmitted by the terminal device, where each first linear combination coefficient group includes first linear combination coefficients of one of s port groups, at least one first linear combination coefficient group includes at least two non-zero coefficients, the s first linear combination coefficient groups are used to determine a first precoding matrix, the s port groups are included in the n port groups. This can improve channel feedback precision of the terminal device, and further help improve performance of transmission between the base station and the terminal device.