Provided are a method and device for uplink information feedback and downlink data transmission, used, when the speed of motion of a terminal is high, for solving the problem of CSI information reported by the terminal being insufficient to track changes on the channel, such that data transmission carried out on the basis of the channel state information reported by the terminal causes seriously degraded performance. The method comprises: a base station obtaining a precoding matrix of a terminal, and an l-th precoding matrix set of L precoding matrix sets corresponding to said precoding matrix; each precoding matrix set of said L precoding matrix sets containing at least one precoding matrix; said at least one precoding matrix originating from a preset codebook, wherein l≤L and L is a positive integer; according to the precoding matrix contained in the obtained l-th precoding matrix set, the base station sending downlink data to the terminal. By means of the precoding matrix set, a relatively wide beam is formed to cover the user, thus guaranteeing downlink transmission for the terminal when it is moving at high speed, improving the reliability of downlink transmission.