The invention discloses a low-voltage DC distribution network protection control method and system. According to the method, differential computation is carried out on transient current to determine whether a fault exists or not; correct fault current direction judgment is carried out on an integral of the transient current, so as to avoid interferences, on protection, of interference signals suchas noise and the like, and improve the protection reliability; and finally, information exchange is carried out between adjacent protection devices to realize fault section judgement. The method is not influenced by network topological changes and has favorable application prospect.