1. A policy control method, comprising: obtaining, by a policy and charging rule function (PCRF) entity, description information of two sub-flows, wherein the two sub-flows belong to an application; generating, by the PCRF entity, a policy and charging control (PCC) rule for each sub-flow of the two sub-flows according to the description information corresponding to each sub-flow; and transmitting, by the PCRF entity, the generated PCC rule to a policy and charging enforcement function (PCEF) entity or a bearing binding and event report function (BBERF) entity, wherein the PCEF entity or the BBERF entity is configured to perform policy control for the two sub-flows.