Provided are a method and apparatus for transmitting information, a base station and a terminal. The method includes: determining transmission configuration information of a transmission region based on a preset size of a data block after channel detection on an unlicensed spectrum succeeds, the transmission region bearing downlink data transmission; generating a scheduling instruction according to the transmission configuration information, and transmitting it to a target terminal; and performing the downlink data transmission according to the transmission configuration information based on the preset size of the data block. The method for transmitting the information provided by the present disclosure may effectively transmit information with an unlicensed spectrum resource, and improve the reliability of information transmission of the unlicensed spectrum.