Far from the traditional network, delay-tolerant network (DTN) is a new kind of network derived by deep space communication. as congestion control is an important factor that directly affects network performance, development, of TN must rely on the perfect congestion control mechanism to ensure reliability, stability, and extensiveness of the network. if TCP widely used a core protocol in internet is directly used in DTN, it coul appear a series of problem such as fairness, stability, and throughput rate, etc. meanwhile, in order to enhance the reability of data delivery in such challenging network, researches have proposed the use of custody transfer protocols, which produces a lot of copies in network and sometimes even aggravates congestion in DTN. this paper shows some limitation of TCP directly applied in DTN, some undersirable effects of custody transfer, and survey of four kinds of distinctive congestion management in DTN.