Embodiments of the present invention disclose a method and an apparatus for handling network congestion, and a system. The method includes: obtaining a transmitted data volume of a flow, and identifying a predictable flow and a non-predictable flow in the flow; collecting statistics about total data transmission volumes of the predictable flow and the non-predictable flow; obtaining a congestion transmission model of the predictable flow, and solving the congestion transmission model to obtain a scheduling policy for the predictable flow; and allocating bandwidths to the predictable flow and the non-predictable flow to obtain a bandwidth allocation result, and sending the bandwidth allocation result and the scheduling policy to the host, so that the host executes the scheduling policy in a scheduling period. This can prevent congestion in advance and reduce a delay of a delay-sensitive flow, and is applicable to a large data center.