A policy control method for multipath transmission, wherein a user equipment, UE, supporting multipath transmission performs service packet transmission by using at least two transmission subflows, and the method comprises: receiving, by a policy decision network element, association information of the at least two transmission subflows in a resource establishment request on one of the at least two transmission subflows from a communication peer, wherein the association information comprises flow identifiers of the at least two transmission subflows, wherein the communication peer comprises the UE, and the UE is an initiator of the resource establishment request; determining, by the policy decision network element, a resource modification policy of at least one transmission subflow in the at least two transmission subflows based on the association information; and sending, by the policy decision network element, the resource modification policy to a forwarding plane network element corresponding to the at least one transmission subflow in the at least two transmission subflows, the method being characterised in that the determining, by the policy decision network element, the resource modification policy of at least one transmission subflow in the at least two transmission subflows based on the association information comprises: obtaining, by the policy decision network element, at least one type of information of load statuses, air interface types, and base station types of the at least two transmission subflows based on the association information; and determining, by the policy decision network element, the resource modification policy of the at least one transmission subflow in the at least two transmission subflows based on the at least one type of information of the load statuses, the air interface types, and the base station types of the at least two transmission subflows. receiving, by a policy decision network element, association information of the at least two transmission subflows in a resource establishment request on one of the at least two transmission subflows from a communication peer, wherein the association information comprises flow identifiers of the at least two transmission subflows, wherein the communication peer comprises the UE, and the UE is an initiator of the resource establishment request; determining, by the policy decision network element, a resource modification policy of at least one transmission subflow in the at least two transmission subflows based on the association information; and sending, by the policy decision network element, the resource modification policy to a forwarding plane network element corresponding to the at least one transmission subflow in the at least two transmission subflows, the method being characterised in that the determining, by the policy decision network element, the resource modification policy of at least one transmission subflow in the at least two transmission subflows based on the association information comprises: obtaining, by the policy decision network element, at least one type of information of load statuses, air interface types, and base station types of the at least two transmission subflows based on the association information; and determining, by the policy decision network element, the resource modification policy of the at least one transmission subflow in the at least two transmission subflows based on the at least one type of information of the load statuses, the air interface types, and the base station types of the at least two transmission subflows. obtaining, by the policy decision network element, at least one type of information of load statuses, air interface types, and base station types of the at least two transmission subflows based on the association information; and determining, by the policy decision network element, the resource modification policy of the at least one transmission subflow in the at least two transmission subflows based on the at least one type of information of the load statuses, the air interface types, and the base station types of the at least two transmission subflows.