A load balancing method, comprising: interacting, by a network management and control center of a basic network system, with a service management and control center of a network service system, and determining a load balancing policy according to entity information about service function execution entities in the network service system, wherein the basic network system comprises a network device comprising a router and a switch or servers functioning as routers and switches and a network management and control center configured to manage and control the network device, and wherein the network service system comprises the service function execution entities distributed on different servers and the service management and control center configured to manage and control each service function execution entity in the network service system; wherein, the interacting, by the network management and control center of the basic network system, with the service management and control center of the network service system, and determining the load balancing policy according to the entity information about the service function execution entities in the network service system comprises: acquiring, by the network management and control center, a load balancing suggestion generated by the service management and control center based on the entity information about the service function execution entities; and taking the load balancing suggestion as the load balancing policy, wherein the entity information comprises address information, service state persistence information and load status information of each service function execution entity, the load balancing suggestion comprises a flow persistence suggestion and a load allocation weight suggestion for the service function execution entity corresponding to each address, and the flow persistence refers to sending all data flows which belong to the same service to the same service function execution entity undergoing service state persistence; generating, by the network management and control center, an execution flow table according to the load balancing policy, and controlling a network device to perform a load balancing operation according to the execution flow table. interacting, by a network management and control center of a basic network system, with a service management and control center of a network service system, and determining a load balancing policy according to entity information about service function execution entities in the network service system, wherein the basic network system comprises a network device comprising a router and a switch or servers functioning as routers and switches and a network management and control center configured to manage and control the network device, and wherein the network service system comprises the service function execution entities distributed on different servers and the service management and control center configured to manage and control each service function execution entity in the network service system; wherein, the interacting, by the network management and control center of the basic network system, with the service management and control center of the network service system, and determining the load balancing policy according to the entity information about the service function execution entities in the network service system comprises: acquiring, by the network management and control center, a load balancing suggestion generated by the service management and control center based on the entity information about the service function execution entities; and taking the load balancing suggestion as the load balancing policy, wherein the entity information comprises address information, service state persistence information and load status information of each service function execution entity, the load balancing suggestion comprises a flow persistence suggestion and a load allocation weight suggestion for the service function execution entity corresponding to each address, and the flow persistence refers to sending all data flows which belong to the same service to the same service function execution entity undergoing service state persistence; generating, by the network management and control center, an execution flow table according to the load balancing policy, and controlling a network device to perform a load balancing operation according to the execution flow table. acquiring, by the network management and control center, a load balancing suggestion generated by the service management and control center based on the entity information about the service function execution entities; and taking the load balancing suggestion as the load balancing policy, wherein the entity information comprises address information, service state persistence information and load status information of each service function execution entity, the load balancing suggestion comprises a flow persistence suggestion and a load allocation weight suggestion for the service function execution entity corresponding to each address, and the flow persistence refers to sending all data flows which belong to the same service to the same service function execution entity undergoing service state persistence; generating, by the network management and control center, an execution flow table according to the load balancing policy, and controlling a network device to perform a load balancing operation according to the execution flow table.