Periodic channel state information feedback method and system

The invention discloses a periodic channel state information feedback method comprising the following steps: determining the bit number of the periodic channel state information needing to be fed back as well as the coded target length by a terminal; judging that the bit number of the periodic channel state information needing to be fed back is not more than the preset threshold value, then coding by adopting the mode of linear block code and intercepting the coded information according to the determined coded target length, or coding by adopting the mode of tail biting convolutional code, and intercepting the coded information according to the determined coded target length; and modulating the intercepted coded information by the terminal and transmitting on an antenna port. The invention correspondingly discloses a channel state information feedback system. The invention has no limitation to the load of the channel state information, thus the application range is wider. The linear block code adopted by the invention can obtain maximum coding gain, thus optimizing the performances.