Provided are a client signal transmission method, apparatus and system and a computer-readable storage medium. The method includes mapping a client signal into a predetermined container corresponding to the client signal; mapping the predetermined container into the corresponding number of first code blocks in a payload area of an optical transport network frame and inserting special idle code blocks during the mapping for rate compensation, where the first code blocks are obtained by dividing the payload area of the optical transport network frame; and sending the optical transport network frame carrying the predetermined container and configuration information of the predetermined container.