The embodiment of the invention provides a multi-path transmission method and device based on an SCTP-CMT transmission protocol. The method comprises the following steps: according to the number of path groups and the transmission stability of each path group, sending grouped data packets through each path group respectively; wherein the path group comprises one or more transmission paths; and ifit is judged that the cache data volume of the receiving end exceeds the specified cache threshold value, reducing the data transmission rate of one or more path groups, or pausing the data transmission of one or more path groups. Due to the fact that more transmission links are used, the data transmission amount is increased, the transmission pressure of each link is reduced, and the data sendingefficiency can be improved. Meanwhile, when the cache of the receiving end is too large, rate control can be carried out according to the cache data size of the receiving end, and the problems that acache region of the receiving end is blocked due to the too large data size, the data receiving efficiency is reduced, and the efficiency of a whole communication link is influenced are solved.