The present disclosure provides an information transmission method, an information transmission device, a communication device and a readable storage medium. The information transmission method includes: obtaining OAM information from an optical network; encapsulating the obtained OAM information to form an OAM frame, the OAM frame including N data frames each having a frame length of L, N varying along with a volume of the OAM information, L being a constant value regardless of the volume of the OAM information; and transmitting the OAM frame. The OAM information is transmitted in a length-constant frame, so it is able to facilitate encoding and decoding of a message, simplifying the processing and reduce the time consumption, and facilitate the extension in accordance with a message content and ensure the extendibility, thereby to solve such problems as complicated processing, being time-consuming, and poor extendibility in the conventional OAM information transmission scheme.