Multipath transmission technology establishes multiple paths between the multiple network interfaces of multi-homed devices at the transport layer, achieving heterogeneous link bandwidth aggregation and providing path redundancy, thereby increasing transmission throughput and reliability. Based on the benefits, multipath transmission technology can be widely used in several application scenarios such as data center network and smartphones, and has important significance for the development of network architecture and the next-generation network revolution. To this end, this paper aims to systematically study multipath transmission technology. Firstly, the basic concepts, standardization process, and application value of multipath transmission are outlined. Secondly, the research focuses on the core mechanisms of multipath transmission technology, including congestion control mechanism, packet scheduling mechanism, path management mechanism, retransmission mechanism, security mechanism and application-oriented mechanism. Each mechanism is elaborated on classification methods, the main research results, and analyzed to summarize the advantages, disadvantages and directions of the mechanism. Furthermore, this paper discusses the application-oriented multipath transmission mechanism design. Finally, this paper proposes five major challenges faced by multipath transmission technology researches and provides prospects for future research directions.