Embodiments of the present application provide a channel state information transmission method. The method includes: receiving downlink data; determining an uplink subframe used to send feedback information of the downlink data, where a first downlink subframe set associated with the uplink subframe includes a first subset and a second subset, and the first subset is a proper subset of the second subset; determining a channel resource used to send the feedback information, where the channel resource includes a first uplink channel resource or a second uplink channel resource; and if sending of r pieces of CSI is configured to be sent, a codebook size of the feedback information corresponds to the first subset, and the determined channel is the second uplink channel resource, sending the feedback information and t pieces of CSI of the r pieces of CSI on the second uplink channel resource.