The invention provides a method for transmitting data streams and a device. According to the method, intermediate nodes transmit the data streams between a source node and a destination node. The data streams comprise a first data stream of which coding form is a fountain code. The method comprises the steps that a first intermediate node receives coded groups sent by the source node or at least one second intermediate node, wherein the coded groups are the groups obtained by coding original groups of the first data stream through utilization of a fountain code technology; and under the condition that an occupancy rate of a first cache queue exceeds a threshold value, the first intermediate node discards the coded groups, wherein the first cache queue is the cache queue allocated to the first data stream by the first intermediate node, and the threshold value shows the maximum occupancy rate allowed by the first cache queue. According to the method and the device, on the premise of not employing a closed control loop, the reliable transmission of the data streams is ensured, the network congestion is reduced, and compared with the prior art, the method and the device have the advantage that the complexity can be reduced.